Exposure calculating apparatus

ABSTRACT

The disclosure relates to an exposure calculation apparatus which includes plural light measuring devices for measuring lights incident on a plurality of regions of a photographing image plane and outputting measured data of the lights; plural devices for detecting the focusing conditions of objects present in a plurality of the regions of the photographing image plane and outputting data on the focusing conditions; a position detecting devices for detecting the position which a main object occupies in the photographing image plane on the data on the focusing condition outputted from the focusing conditions detecting devices; calculation device for making a plurality of calculations each of which is made depending on at least one of the data of measured lights outputted from the light measuring devices; and selecting devices for selecting one of the plurality of calculations on the position detected by the position detecting devices and the data on the focusing conditions of the position.

This application is a divisional, of application Ser. No. 07/453,259,filed Dec. 20, 1989, now U.S. Pat. No. 4,977,423, which is acontinuation application of Ser. No. 07/307,845, filed on Feb. 8, 1989,now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exposure calculating apparatus foruse in, for example, a camera, and more particularly, to an apparatuswhich calculates an exposure control data so as to expose a main objectproperly by dividing a photographing image plane into a plurality ofregions and measuring the luminance information of respective regions.

2. Description of the Related Art

An exposure control apparatus is disclosed, for example, in U.S. Pat.No. 4,423,936 according which a photographing image plane is dividedinto a plurality of regions, a region in which a main object is present(hereinafter referred to as the main zone) is detected from a pluralityof the regions, and an exposure control is performed based on themeasured brightness or luminance value of the main zone and the measuredluminance values of the other regions. According to this apparatus, alight measuring signal such as an infrared light measuring signal isemitted toward a photographing field, and the photographing distances ofobjects present in three different regions of the photographing fieldare found, whereby the region in which the nearest object (main object)is present, namely, the main zone is detected. The luminances of thethree regions are detected and an exposure control is carried out basedon the measured values of light from the main zone and the other regionsso as to obtain correct exposure.

Another exposure calculating apparatus is disclosed in Japanese PatentLaid-Open Publication No. 203022/1987. According to this apparatus, thesize of the image of a main object is presumed according to the objectdistance information and the focal length of the photographing lens, anda light measuring range is changed according to the size. According tothe apparatus, the size of the image of the main object located in thecenter of the photographing image plane is presumed based on the objectdistance information and the information of the focal length of thephotographing lens, and the light measuring region is changed accordingto the size of the image of the main object, whereby light measuringinformation to properly expose the main object is outputted.

In the exposure calculating apparatus according to U.S. Pat. No.4,423,936, the position of the main object is considered besides themeasured values, but the size of the main object is not considered.Accordingly, the main object cannot always be exposed properly. Forexample, if the main object is small, a lot of light reflected fromobjects other than the light reflected from the main object are incidenton the region to be measured. Therefore, the luminance of the mainobject cannot be accurately measured.

In the exposure calculating apparatus according to Japanese PatentLaid-Open Publication No. 203022/1987, it is indispensable that the mainobject is present in the center of the photographing image plane.Therefore, if the main object is not located in the center of thephotographing image plane, it is impossible to properly expose the mainobject.

SUMMARY OF THE INVENTION

Accordingly, an essential object of the present invention is to providean improved exposure calculating apparatus which can overcome suchdisadvantages as described above, namely, an exposure calculatingapparatus which calculates exposure control data so that a main objectcan be properly exposed under any circumstances.

In accomplishing this and other objects, according to one preferredembodiment of the present invention, an improved exposure calculatingapparatus is provided comprising plural first means for measuring lightsincident on a plurality of regions of a photographing image plane andoutputting data of the measured light, plural second means for detectingthe focusing conditions of objects present in a plurality of regions ofthe photographing image plane and outputting data on the focusingcondition, third means for detecting the position in which the mainobject is present based on the data on the focusing conditions outputtedfrom the second means, fourth means for selecting at least one data froma plurality of the data of the measured light outputted from the firstmeans based on the position of the main object, detected by the thirdmeans and the data on the focusing condition in the position in whichthe main object is present, and fifth means for calculating exposurecontrol data based on the data of the measured light selected by thefourth means.

According to another preferred embodiment of the present invention, anexposure calculating apparatus as described below is provided. Theexposure calculating apparatus comprises plural first means formeasuring light incident on a plurality of regions of a photographingimage plane and outputting data of the measured light, plural secondmeans for detecting the focusing conditions of objects present in aplurality of regions of the photographing image plane and outputtingdata on the focusing conditions, third means for detecting the positionof main object based on the data on the focusing conditions outputtedfrom the second means, fourth means for inputting focal length data of aphotographing lens, fifth means for selecting at least one data from aplurality of data of the measured light outputted from the first meansbased on the position of the main object detected by the third means andthe focal length data inputted by the fourth means, and sixth means forcalculating exposure control data based on the data selected by thefifth means.

According to still another preferred embodiment of the presentinvention, an exposure calculating apparatus as described below isprovided. The exposure calculating apparatus comprises plural firstmeans for measuring light incident on a plurality of regions of aphotographing image plane and outputting measured data of the light,plural second means for detecting the focusing conditions of objectspresent in a plurality of regions of the photographing image plane andoutputting data on the focusing conditions, third means for detectingthe position of the main object based on the data on the focusingconditions outputted from the second means, fourth means for detectingthe size of the image of the main object, fifth means for selecting atleast one data from a plurality of the data outputted from the firstmeans based on the position of the main object detected by the thirdmeans and the size of the main object detected by the fourth means, andsixth means for calculating exposure control data based on the dataselected by the fifth means.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome apparent from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a circuit diagram of a camera system which embodies thepresent invention;

FIG. 2 is a view showing ranges in which light is measured and regionsin which focusing conditions are detected in the camera system whichembodies the present invention;

FIG. 3 is the circuit diagram of the flash emitting device to be usedfor the camera system which embodies the present invention;

FIG. 4 through FIG. 29 are flowcharts showing the control to beperformed by a microcomputer provided in the camera of a camera systemwhich embodies the present invention;

FIGS. 30a, 30b through FIG. 34 are flowcharts showing the control to beperformed by the microcomputer provided in the flash emitting device ofthe camera system which embodies the present invention;

FIG. 35 is a graph showing a photographing state recorded in anautomatic emission mode in the camera system which embodies the presentinvention;

FIG. 36 is a flowchart showing an essential part of a modification ofthe flowchart shown in FIG. 5;

FIGS. 37a and 37b are flowcharts showing essential parts of amodification of the flowchart shown in FIG. 8;

FIGS. 38a, 38b, 38c and 38d are flowcharts showing essential parts of amodification of the flowchart shown in FIGS. 13a and 13b;

FIG. 39 is a flowchart showing an essential part of a modification ofthe flowchart shown in FIG. 17;

FIG. 40 is a flowchart showing an essential part of a modification ofthe flowchart shown in FIG. 18;

FIG. 41 is a flowchart showing an essential part of a modification ofthe flowchart shown in FIG. 20;

FIGS. 42a, 42b and 42c are flowcharts showing essential parts of amodification of the flowchart shown in FIGS. 23a, 23b, 23c and 23d;

FIG. 43 is a flowchart showing an essential part of a modification ofthe flowchart shown in FIG. 31;

FIG. 44 is a flowchart showing an essential part of a modification ofthe flowchart shown in FIGS. 32a and 32b;

FIGS. 45a and 45b are flowcharts showing an essential part of amodification of the flowchart shown in FIGS. 33a and 33b; and;

FIGS. 46a, 46b, 46c and 46d are views showing, respectively, lightmeasuring ranges in the camera system which embodies the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiments of the present invention is described with reference tothe drawings.

Hardware Description of System

Referring now to the drawings, there is shown in FIG. 1, an electriccircuit of a camera system which embodies the present invention. Thecamera system of the embodiment has four exposure control modes, aprogram mode (P), a shutter speed priority mode (S), an aperturepriority mode (A), and a manual mode (M).

Referring to FIG. 1, a microcomputer MCB provided in a camera bodycontrols the entire camera system. The microcomputer MCB is connectedthrough a serial data bus SDB to a light measuring interface LIF, aflash circuit FLC, a display circuit DSP, and a lens circuit LEC. Themicrocomputer MCB is also connected to an AF interface AIF and a drivecircuit DDR through data buses ADB and DDB, respectively.

The light measuring interface LIF is connected to a light measuringcircuit LMA connected with six photodiodes PD₀ ˜PD₅. The photodiodes PD₀˜PD₅ are disposed so that each of them receives the light incident on adifferent portion of a photographing image plane. The ranges in whichlight is measured by the respective photodiodes PD₀ ˜PD₅ are as shown inFIG. 2. That is, the photodiode PD₀ is disposed to receive a lightincident on a circular portion 1 located in the center of aphotographing image plane FLM; the photodiode PD₁ to receive a lightincident on a "C"-shaped portion 2 located on the left hand of thecircular portion 1; the photodiode PD₂ to receive a light incident on a"C"-shaped portion 3 located on the right hand of the circular portion1; the photodiode PD₃ to receive a light incident on a "C"-shapedportion 4 located on the upper hand of the circular portion 1; thephotodiode PD₄ to receive a light incident on a "C"-shaped portion 5located on the lower hand of the circular portion 1; and the photodiodePD₅ to receive a light incident on a portion 6 of a rectangular rangeLMR in which a light is measured excluding the above-described portions1 through 5.

The above-described manner of determining the regions in which light ismeasured allows a fine adjustment of a diameter of the area for spotmetering according to the size of an object to be photographed with theimportance attached to the luminous quantity of the center portion,further, exposure control is performed with the weight applied to thebright or luminous quantity of a dark portion by utilizing thedifference in the brightness or luminances between the portion 4disposed relatively upper in the light measuring region LMR and theportion 5 disposed relatively lower therein. Taking a photograph under abright sky as an example, the luminance of the region 4 is much greaterthan that of the region 5. In this case, the weight of the luminousvalue of the region 4 is reduced, whereby the main object can be exposedproperly.

As apparent from FIG. 1, the anodes of all the photodiodes PD₀ ˜PD₅ aregrounded.

The light measuring interface LIF provided with an A-D converterconverts the analog data of the output from the light measuring circuitLMA to digital data, thus outputting a digitized signal to themicrocomputer MCB. The light measuring interface LIF provided with a D-Aconverter converts digital data corresponding to the controlled lightquantity of a flash light transmitted from the microcomputer MCB throughdata bus SDB into the analog data, thus outputting an FSL signal to theflash light measuring circuit LMF.

The flash light measuring circuit LMF measures a flash light and outputsa flash stopping signal FSTP for stopping a flash emission when anobject is exposed properly. The flash light measuring circuit LMFreceives a light reflected from a film through a photodiode PDF andconverts the electric current corresponding to the intensity of thereceived light into a voltage by performing a logarithmic compression,and then, logarithmically expands the addition of the logarithmicallycompressed voltage and the FSL signal, which is converted into electriccurrent, then integrates the electric current and outputs a flashstopping signal FSTP for stopping a flash emission when the integratedquantity has reached an appropriate value.

The detailed description of the flash circuit FLC will be made later.

The display circuit DSP displays various photographic information suchas an aperture value, a shutter speed, and an exposure control mode,reads the ISO sensitivity of a film according to the relationshipbetween a film cartridge and contacts CAS, and transfers the data of thefilm sensitivity to the microcomputer MCB. The display circuit DSP hasan individual microcomputer. A reference clock generating circuit X₁generates a reference clock of the microcomputer of the display circuitDSP.

The lens circuit LEC provided for respective photographing lensesoutputs information thereof, for example, focal lengths, minimumaperture values.

The AF interface AIF receives a control signal from the microcomputerMCB through a data bus ADB. Based on the control signal, the AFinterface AIF controls the operation of a light receiving circuit AFD,for detecting focusing condition, including CCD line sensors, through asignal line AFS. The AF interface AIF receives the analog data of therespective pixels or picture elements of the CCD line sensors throughthe signal line AFS, then converts the analogue data into digital datawhich is outputted to the microcomputer MCB through the data bus ADB.The light receiving circuit AFD for detecting focusing condition hasthree CCD line sensors ISL₀, ISL₁, and ISL₂ which are used to detect thein-focus states of objects located at positions corresponding to theregions shown by broken lines in FIG. 2. More specifically, the CCD linesensor ISL₀ is used to horizontally detect the in-focus state of anobject disposed at the center portion (zero zone) of the photographingimage plane FLM. The CCD line sensor ISL₁ is used to vertically detectthe in-focus state of the object disposed on the left hand (first zone)of the center thereof. The CCD line sensor ISL₂ is used to verticallydetect the in-focus state of the object disposed on the right hand(second zone) of the center thereof. Upon completion of the CCDintegrations of the CCD line sensors ISL₀, ISL₁, and ISL₂, the AFinterface AIF outputs an integration completion signal AFFN of an "L"level to an interruption terminal INT₁. Thus the microcomputer MCB isenabled for an interruption.

A DC-to-DC converter VG boosts the voltage of a battery BA for a directcurrent power source, thus supplying the respective circuits with twokinds of voltages HV and LV (HV>LV). The higher voltage HV is suppliedto the AF interface AIF and the light receiving circuit AFD. The lowervoltage LV is supplied to the light measuring interface LIF, the lightmeasuring circuit LMA, the flash light measuring circuit LMF, the lenscircuit LEC, the drive circuit DDR, and encoders ENAP and ENLE. Thebattery BA powers the microcomputer MCB, the display circuit DSP, andthe motor control circuit MOD through a power source feeding line VDD.

Next, switches are described hereinbelow.

A light measuring switch S₁ is turned on when an unshown release buttonis pressed to a first stroke (a first press). When the light measuringswitch S₁ is turned on, a light measuring and the detection of anin-focus state are started by the microcomputer MCB. The value of ameasured light when an AE lock switch is turned on is stored. When areset switch SRS is turned on, the entire system is initialized. Everytime an exposure control mode change-over switch MOS is changed from OFFto ON, the exposure control mode is changed in the order of P, S, A, M,and to P. Every time a data setting switch US is changed from OFF to ON,a shutter speed increases by 1 Ev or an aperture value increases by 1/2Ev. Every time a data setting switch DS is changed from OFF to ON, theshutter speed is reduced by 1 Ev or the aperture value is reduced by 1/2Ev. When an unshown release button is depressed to a second stroke (by asecond press), a release switch S₂ is turned on. Accordingly, when therelease switch S₂ is ON, the light measuring switch S₁ is also ON. Whenthe switch S₂ is turned on, an exposure control operation is started bythe microcomputer MCB. A photograph completion detection switch S₄ isturned on when a mirror (unshown) pivots downwards, the aperture(unshown) fully opens, and a second shutter curtain (unshown) completesits movement upon completion of an exposure, and thereafter, is turnedoff when every one frame of a film is wound and the shutter, mirror, anddiaphragming mechanism are cocked. The operations of the data settingswitches US and DS changes the aperture value with the switch ASS turnedon when the exposure control mode is (M) mode, while the shutter speedis changed by the operations of the data switches US and DS with theswitch ASS turned off.

As shown in FIG. 1, the light measuring switch S₁, the AE lock switchALS, the reset switch SRS, the mode change-over switch MOS, the datasetting switches US and DS are connected to an interruption terminalINT₀ through an AND circuit AN₀ with one end of each of these switchesgrounded. Accordingly, the microcomputer MCB starts an interruptoperation when either of the light measuring switch S₁, the AE lockswitch ALS, the reset switch SRS, the mode change-over switch MOS, thedata setting switches US and DS is turned on.

Although not shown, each of the ungrounded terminals of these switchesis pulled up by the voltage of the battery BA (VDD), and needless tosay, a chattering eliminator is provided for these switches.

The microcomputer MCB outputs control data to the drive circuit DDRthrough the data bus DDB. The control data are decoded to control fourmagnets RLM, APM, 1CM, and 2CM, and motor control data is outputted fromthe drive circuit DDR to a motor control circuit MOD. When theattracting portions of release magnets RLM repel each other, adiaphragming member and the mirror are disengaged from an engagingmember, and then, the diaphragming member starts an aperturesize-reducing operation and the mirror pivots upwards, while thediaphragm member stops the diaphragming operation when the attractingportions of diaphragming magnets APM repel each other. When theattracting portions of the magnets 1CM and 2CM for traveling shuttersrepel each other, respectively, the first shutter curtain (unshown) andthe second shutter curtain are disengaged from engaging members such assprings and start traveling. When electric current flows through thecoils of the release magnet RLM, the magnet APM, the magnets 1CM and 2CMcomprising permanent magnets, coils, and attracting portions,respectively, the attracting portions thereof repel each other.

The motor control circuit MOD controls the clockwise andcounterclockwise rotations of a film sending motor MOFI and a lens drivemotor MOL in response to the data transmitted from the drive circuitDDR.

The encoder ENAP detects the position of the diaphragm, while theencoder ENLE detects the rotation amount of the lens drive motor MOL,namely, the movement amount of the lenses. The output pulses of theencoders ENAP and ENLE are inputted to the count terminal CNT of themicrocomputer MCB through a multiplexer comprising AND circuits AN₃ andAN₄ and an OR circuit OR₂.

A reference clock generating circuit XB comprises a crystal oscillatorand a capacitor. A reference clock STCK outputted from the referenceclock output terminal STCK of the microcomputer MCB is applied both tothe light measuring interface LIF and the AF interface AIF.

Flash circuit

FIG. 3 is a block diagram showing the flash circuit FLC shown in FIG. 1.The flash circuit FLC is provided in a flash emitting device removablymounted on the camera body and connected to the circuit of the camerabody through nine contacts J₀ ˜J₈. The contacts J₀ through J₄ composethe data bus SDB shown in FIG. 1.

A microcomputer MCF controls the flash circuit FLC independently of themicrocomputer MCB shown in FIG. 1.

Every time the flash stopping mode switch-over switch ATS is turned on,the flash stopping mode is switched alternately to an automatic flashstopping mode and manual flash stopping mode. In the automatic flashstopping mode, a flash emission is stopped in response to the flashstopping signal FSTP inputted from the flash light measuring circuit LMFto the flash circuit FLC through the terminal J₆.

Every time the illumination range change-over switch VCS is turned on, apanel mounted in front of the emission portion is moved. As a result,the illumination range is changed so that a flash light may selectivelycover the field angle of a photographing lens having the focal length of"automatic", 28 mm, 35 mm, 50 mm and 70 mm. "Automatic" herein means amode which is automatically set to the focal length of a photographinglens. For example, if the focal length of a photographing lens is 35 mm,every time the switch VCS is turned on, the illumination range ischanged so that a flash light covers the field angle of a photographinglens having the focal length of 35 mm, 28 mm, 35 mm, 50 mm, 70 mm, 35mm - - - . In the case of a zoom lens, when the switch VCS is operatedto set the illumination range to the "automatic", the illumination rangeis automatically changed every time a zooming is carried out.

Every time an emission mode change-over switch MES is turned on, theemission mode is switched in turn to forced emission, automaticemission, non-emission and forced emission.

As shown in FIG. 3, each one of the ends of these switches ATS, VCS, andMES is grounded and the other ends thereof are connected to theinterruption terminal INTA of the microcomputer MCF through AND circuitAN₆. Accordingly, when any one of these switches ATS, VCS, and MES isturned on, the microcomputer MCF is enabled for an interruption.Similarly to the switch S₁ as shown in FIG. 1, these switches ATS, VCS,and MES are pulled up and a chattering eliminator is provided.

A display circuit FDP displays flash information. A charge completionindicator CHD makes an indication when the main capacitor MC has beencharged to a predetermined voltage, for example, 300 V. The indicationis made by the charge completion indicator CHD after data is transferredfrom the microcomputer MCB and only when a flash indication signal FDISindicates that the indication is enabled. The flash indication signalFDIS will be described later. A flash stopping indicator FCD operatesfor a certain period, for example, three seconds, after the flashstopping signal FSTP is outputted from the flash light measuring circuitLMF so as to inform a photographer that a flash emission has beenappropriately made. Each of the indicators CHD and FCD comprise an LEDwhich emits a different color from the other.

A motor control circuit MDR controls a motor MOFL. The motor MOFL movesa panel disposed in front of the flash emission portion so that anillumination range is changed.

A position detecting circuit ZCP, having an encoder which outputs asignal according to the rotation of the motor MOFL, detects the positionof the panel which is moved by the motor MOFL.

A reference clock generating circuit XF comprises a crystal oscillatorand a capacitor.

A flash control circuit FCC outputs signals STA and STOP so that a flashemission portion XE starts or stops a flash emission.

A voltage stabilizing circuit CVG stabilizes a voltage supplied to themicrocomputer MCF even when the voltage of the battery BA for the directcurrent power source increases or decreases.

A DC-to-DC converter DD, a rectifier diode DI, the main capacitor MC,the charge completion detecting means NE, the flash emission portion XE,and an emission control circuit XCC comprise a well-known flash circuit.In response to an emission start signal STA outputted from the flashcontrol circuit FCC, the emission control circuit XCC comprising athyristor, a trigger circuit, and a commutation capacitor operates thetrigger circuit, outputs a trigger signal from the terminal TR thereofso as to trigger the flash emission portion XE, and at the same time,turns on the thyristor and makes the flash emission portion XCC emitflash light. The emission control circuit XCC discharges the commutationcapacitor in response to the emission stop signal STOP outputted fromthe flash control circuit FCC, whereby the thyristor is turned off andmakes the flash emission portion XE stop emitting flash light.

Switching transistors TR₀ and TR₁ control, respectively the operation ofthe DC-to-DC converter DD and the charge completion means NE in responseto the signal outputted from the microcomputer MCF.

In the embodiment, a neon tube is used as the charge completiondetecting means NE, and a xenon tube is used as the flash emissionportion XE.

Terminal of microcomputer

The functions of the terminals of the microcomputers MCB and MCF (inputand output signals and data and the operation of the camera system) arelisted in Tables 1 and 2.

                  TABLE 1                                                         ______________________________________                                        terminal                                                                             I/O                                                                    ______________________________________                                        P.sub.0                                                                              output   A-D control terminal                                                          A-D converter is actuated by "L"                              P.sub.1                                                                              output   chip select terminal                                                          light measuring interface LIF is selected by                                  "L"                                                           P.sub.2                                                                              output   chip select terminal                                                          flash circuit FLC is selected by "L"                          P.sub.3                                                                              output   chip select terminal                                                          display circuit DSP is selected by "L"                        P.sub.4                                                                              output   chip select terminal                                                          lens circuit LEC is selected by "L"                           P.sub.5                                                                              output   power control terminal                                                        DC-to-DC converter VG is actuated by                                          "L"                                                           P.sub.6                                                                              input    terminal for detecting light measuring                                        switch S.sub.1.                                                               "L" when S.sub.1 is ON                                        P.sub.7                                                                              input    terminal for detecting AE lock switch ALS                                     "L" when ALS is ON                                            P.sub.8                                                                              input    terminal for detecting reset switch SRS                                       "L" when SRS is ON                                            P.sub.9                                                                              input    terminal for detecting mode change-over                                       switch MOS                                                                    "L" when MOS is ON                                            P.sub.10                                                                             input    terminal for detecting data setting switch US                                 "L" when US is ON                                             P.sub.11                                                                             input    terminal for detecting data setting switch                                    DS                                                                            "L" when DS is ON                                             P.sub.12                                                                             input    terminal for detecting release switch S.sub.2                                 "L" when S.sub.2 is ON                                        P.sub.13                                                                             input    terminal for detecting photographing                                          completion detecting switch S.sub.4                                           "L" when S.sub.4 is ON                                        P.sub.14                                                                             input    terminal for detecting change-over switch                                     ASS                                                                           "L" when ASS is ON                                            P.sub.15                                                                             output   encoder selection terminal                                                    ENAP is selected by "H"                                                       ENLE is selected by "L"                                       STCK   output   reference clock output terminal                                               reference clock is outputted to                                               interfaces LIF and AIF                                         ##STR1##                                                                             input    interruption terminal                                                        interruption starts in synchronization                                        with fall                                                      ##STR2##                                                                             input    interruption terminal                                                        interruption starts in synchronization                                        with fall                                                     SIO.sub.0                                                                            input    serial data input/output terminal                                    & output                                                               SIO.sub.1                                                                            input    serial data input/output terminal                                    & output                                                               DDO    output   drive data output terminal                                    ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        terminal                                                                             I/O                                                                    ______________________________________                                        P.sub.20                                                                             input    terminal for detecting flash stopping                                         mode change-over switch ATS                                                   "L" when ATS is ON                                            P.sub.21                                                                             input    terminal for detecting illumination range                                     change-over switch VCS                                                        "L" when VCS is ON                                            P.sub.22                                                                             input    terminal for detecting emission mode                                          change-over switch MES                                                        "L" when MES is ON                                            P.sub.23                                                                             input    read/write detecting terminal                                                 "H" when data is outputted                                                    "L" when data is inputted                                     P.sub.24                                                                             output   charge completion terminal                                                    charge completion is indicated by "H"                         P.sub.25                                                                             output   terminal for outputting "H" level signed                                      when the flash light is correctly emitted                     P.sub.26,                                                                            output   motor control terminal which output data                      P.sub.27        for controlling rotation and stop of motor                                    MOFL                                                          P.sub.28,                                                                            input    position detecting terminals                                  P.sub.29        position information of emission panel is                                     inputted from position detecting circuit ZCP                  P.sub.30                                                                             output   terminal for controlling DC-to-DC                                             converting                                                                    DC-to-DC converter DD is actuated                                             by " H"                                                       P.sub.31                                                                             output   control terminal for detecting charge                                         completion                                                                    charge completion is carried out by "H"                                       charge completion detection is prohibited                                     by "L"                                                        P.sub.32                                                                             input    charge completion detecting terminal                                          charge completion state is detected by                                        quantity of supplied electric current                         P.sub.33                                                                             input    terminal for detecting by "H" that                                            flash light is correctly emitted                              P.sub.34                                                                             output   terminal for controlling flash stopping                                       operation                                                                     flash stopping signal is ignored by "H"                       P.sub.35                                                                             output   emission control terminal                                                     emission is allowed by "L"                                    SCK    input    reference clock input terminal                                                serial data is inputted or outputted in                                       synchronization with the reference clock                      SIN    input    serial data input terminal                                    SOUT   output   serial data output terminal                                   FDO    output   display data output terminal                                                  serially outputs display data to                                              display circuit FDP                                            ##STR3##                                                                             input    interruption terminal                                                        interruption starts in synchronization                                        with fall                                                      ##STR4##                                                                             input    interruption terminal                                                        interruption starts in synchronization                                        with fall                                                     ______________________________________                                    

SOFTWARE

The control to be performed by the camera system in this embodiment isdescribed hereinbelow.

Flag

Table 3 shows flags to be used in this system and the contents which theflags signify. The upper stages of Table 3 indicate the states at thetime when the flags are set and the lower stages thereof show the statesat the time when the flags are reset. Flags AMF and STF are used by themicrocomputer MCF provided in the flash circuit FLC. The flag STF isset, as described later, when the flash emitting device is mounted on anexclusive camera applicable to the flash emitting device and when asignal is transferred from the camera to the flash emitting device andis reset when a signal to be transmitted from the camera or a signalgenerated by a manual operation is not inputted to the microcomputer MCFfor a certain period. In other words, when the flash emitting device isoperating as part of the camera system, the flag STF is set and when theflash emitting device is operating independently of the camera system,the flag STF is reset.

                  TABLE 3                                                         ______________________________________                                                                   upper stage: set (1)                                                          lower stage:                                       flag  content              reset (0)                                          ______________________________________                                        AEF   exposure calculation is                                                                            completed                                                                     not completed                                      ALF   AE lock switch ALS is                                                                              ON                                                                            OFF                                                BLAF  AE lock by AE lock switch ALS is                                                                   completed                                                                     not completed                                      BLFF  AE lock due to in-focus state is                                                                   completed                                                                     not completed                                      DDFF  low contrast search is                                                                             completed                                                                     not completed                                      FDF   AF operation is      not completed                                                                 completed                                          FIHF  focusing condition detection is                                                                    prohibited                                                                    permitted                                          FLF   focus lock is        completed                                                                     not completed                                      LCF   focusing condition data is                                                                         reliable                                                                      reliable                                           LLF   low luminance                                                                 (camera shake may occur)                                                      non-low luminance                                                       RIHF  release operation is prohibited                                                                    permitted                                          AMF   flash stopping mode is                                                                             automatic                                                                     otherwise                                          STF   camera system is     in operation                                                                  not in operation                                   ______________________________________                                    

Data

Table 4-1 shows the display data to be transferred to the displaycircuit DSP and the contents of the data. In response to the datatransferred from the micromputer MCB, the display circuit DSP stores thedata in the memory (RAM) provided therein, and display the informationindicated by the data by means of a liquid crystal display, an LED, andso on. Supporting that the content of the data AFD is "01", themicrocomputer provided in the display circuit DSP actuates the LEDprovided in a finder (not shown), whereby the photographer knows that anin-focus state has been obtained. On the other hand, if the content ofthe data AFD is "10", the microcomputer provided in the display circuitDSP flashes the LED, whereby the photographer knows that it isimpossible to detect focusing condition. Data AVD showing a controlaperture value Avs and data CND indicating the number of exposed framesof a film are indicated by numerals by the liquid crystal display atopthe camera body The information on display data AFD, ALD, AVD, FLD₁,FLD₂, MOD, and TVD are displayed in the finder. The information ondisplay data AVD, CND, MOD, SVD, and TVD are displayed atop the camera.

                  TABLE 4-1                                                       ______________________________________                                        display                                                                       data  content of indication                                                   ______________________________________                                        AFD   focusing condition                                                                              00 . . . indication OFF                                                       01 . . . in-focus                                                             10 . . . undetectable                                 ALD   AE lock by AE lock                                                                               0 . . . not AE-locked                                      switch ALS         1 . . . AE-locked                                    AVD   control aperture value (Av)                                             CND   number of exposed frames                                                FLD.sub.1                                                                           flash information 00 . . . indication OFF                                                       01 . . . charge completed                                                     10 . . . flash light is                                                           correctly emitted                                 FLD.sub.2                                                                           flash information 00 . . . indication OFF                                                       01 . . . emission mode                                                        10 . . . non-emission mode                                                    11 . . . being charged                                MOD   exposure control  00 . . . P mode                                             mode              01 . . . S mode                                                               10 . . . A mode                                                               11 . . . M mode                                       SVD   film sensitivity (Sv)                                                   TVD   control exposure time (Tv)                                              ______________________________________                                    

Table 4-2 shows the data to be transferred to the display circuit FDPprovided in the flash emitting device and the contents of the data.Similarly to the display circuit DSP provided in the camera, in responseto the data outputted from the microcomputer MCF, the display circuitFDP stores the data in the memory (RAM) provided therein, and displaysthe information of the data by means of a liquid crystal display. Thedisplay portion where the information is displayed is provided on theback side of the flash emitting device. The display data FND and ISDindicate a film sensitivity and a control aperture value bothtransferred from the camera, respectively. The display data FDDindicates the distance range, an object in the distance range beingexposed correctly, calculated depending on an aperture value, a filmsensitivity, both transferred from the camera body, and the maximum andminimum emission amount determined by the illumination range ofrespective photograph. When an illumination range is "automatic", "1" isstored in the most significant bit of the display data FZD and when anillumination range is "manual", (28 mm, 35 mm, 50 mm, 70 mm), "0" isstored therein. Data indicating an illumination range is stored in thelow-order three bits of the data FZD.

                  TABLE 4-2                                                       ______________________________________                                        display                                                                       data  content of indication                                                   ______________________________________                                        AMD   flash stopping mode                                                                             10 . . . manual light                                                             amount                                                                        adjustment                                                                01 . . . automatic emission                           FDD   the distance range                                                      FMD   emission mode     00 . . . forced emission                                                      01 . . . automatic emission                                                   10 . . . non-emission                                 FND   control aperture value (Av)                                             FZD   illumination range                                                                              0*** . . . automatic                                                          1*** . . . manual                                                             *001 . . . 28 mm                                                              *010 . . . 35 mm                                                              *011 . . . 50 mm                                                              *100 . . . 70 mm                                      ISD   film sensitivity (Sv)                                                   ______________________________________                                    

Table 5 shows data transferred between the microcomputer MCB and theflash circuit FLC and the contents signified by the data. As shown inthe table, the data consist of eight bits. Data CFR₀ through CFR₃ aretransferred from the microcomputer MCB to the flash circuit FLC. DataFCR₀ and FCR₁ are transferred from the flash circuit FLC to themicrocomputer MCB. High-order two bits CFR₀₇ and CFR₀₆ of the data CFR₀correspond to the exposure control mode register MOR and their contentsare the same as the display data MOD (refer to Table 4-1). The mostsignificant bit CFR₃₇ (SYS) of the data CFR₃ is set when the resetswitch SRS is turned on (system reset) and reset when the reset switchSRS is OFF. The seventh bit CFR₃₆ of the data CFR₃ corresponding to theindication signal FDIS is set when the display circuit FDP and theindicator CHD provided in the flash circuit FLC are prohibited frommaking indications and reset when they are allowed to make indications.The sixth bit CFR₃₅ (FNS) of the data CFR₃ is reset when a flashemission is permitted and set when the flash emission is prohibited. Thehigh-order two bits FCR₀₇,08 (FMR) of the data FCR₀ indicates the flashemission mode. Similarly to the display data FMD shown in Table 4-2,"00" indicates the forced emission mode; "01", automatic emission mode;and "10", non-emission mode. The sixth bit FCR₀₅ (RDY) of the data FCR₀is set when the main capacitor MC provided in the flash circuit FLC ischarged in a predetermined voltage (300 V). The fifth bit FCR₀₄ (OK) ofthe data CFR₀ is set for a given period after a flash emission isstopped according to the flash stopping signal FSTP under the automaticflash stopping mode and reset at other times. The fourth bit FCR₀₃ (FON)of the data FCR₀ is set when the flash emitting device is operating,i.e., when the flash device is mounted on the camera and the powersource therefor is ON.

The low-order six bits of the data CFR₀ indicate the ISO sensitivity Svof a film. The data CFR₁ and CFR₂ indicate the focal length Fv and theaperture value Av of a photographing lens, respectively. The low-orderfive bits of the data CFR₃ indicates a compensation amount α for anemission amount (described later). The data FCR₁ indicates the maximumemission amount Iv of the flash emitting device. The low-order threebits of the data FCR₀ are not used (these bits are shown by "*" in thetable.)

                  TABLE 5                                                         ______________________________________                                        data  7       6       5     4    3    2    1    0                             ______________________________________                                        CFR.sub.0                                                                           MOR         film sensitivity (Av)                                       CFR.sub.1                                                                           focal length (Fv)                                                       CFR.sub.2                                                                           aperture value (Av)                                                     CFR.sub.3                                                                           SYS     FDIS    FNS   compensation amount of                                                        emission amount (α)                         FCR.sub.0                                                                           FMR         RDY     OK   FON  *    *    *                               FCR.sub.1                                                                           maximum emission amount (Iv)                                            ______________________________________                                         MOR: exposure control mode                                                    SYS: set only in the case of system reset                                     FDIS: set when the indication made in flash emitting device is prohibited     FNS: set when flash emission is prohibited                                    FMR: emission mode                                                            RDY: set when the capacitor MC is charged in a predetermined voltage          OK: set when flash light is correctly emitted                                 FON: set when power source of flash emitting device is ON                

Flowchart Microcomputer MCB

FIG. 4 through 29 are flowcharts showing the operation (operation of themicrocomputer MCB) of the camera system, namely, excluding a flashemitting device, of the embodiment.

Interruption INT₀

When either of the light measuring switches S₁, the AE lock switch ALS,the reset switch SRS, the mode change-over switch MOS, the data settingswitches US and DS is turned on, the voltage level of the interruptionterminal INT₀ becomes low and in synchronization of the fall of thesignal level, the microcomputer MCB starts its operation in accordancewith the flowchart shown in FIG. 4.

First, at step #1, the microcomputer MCB actuates the reference clockgenerating circuit XB so that the reference clock STCK is outputted fromthe reference clock outputting terminal STCK. At step #2, the signallevel of the power control terminal P₅ is set to "L" to operate theDC-to-DC converter circuit VG. At steps #3, #10, #13, and #15, themicrocomputer MCB determines which of the switches causes theinterruption INT₀. If the voltage level of the terminal P₆ is "L" atstep #3, it is decided that the interruption signal is inputted to theinterruption terminal INT₀ (hereinafter referred to as the interruptionINT₀ occurs) due to the operation of the light measuring switch S₁, sothat the program goes to step #4 and if the voltage level of theterminal P₆ is "H" (hereinafter referred to as "terminal P₆ is "H" or"L" instead of "the level of the terminal is "H" or "L"), the programgoes to step #10. If the terminal P₇ is "L" at step #10, it is decidedthat an interruption INT₀ occurs by the operation of the AE lock switchALS, so that the program goes to step #11, and if the terminal P₇ is"H", the program goes to step #13. If the terminal P₈ is "L" at step#13, it is decided that an interruption INT₀ is caused by the operationof the reset switch SRS, then the program goes to step #14 (subroutine"system reset"), and if the terminal P₈ is "H", the program goes to step#15. If the terminal P₉ is "L" at step #15, it is determined that aninterruption INT₀ occurs by the operation of the mode change-over switchMOS, then the program goes to step #16 (subroutine "mode conversion").If the terminal P₉ is "H" at step #15, it is decided that aninterruption INT₀ is caused by the operation of the data settingswitches US or DS and the program goes to step #17 (subroutine "dataconversion"). When the program goes to either of subroutines #14, #16,and #17, the program goes to STOP routine after the program returns fromthe subroutine and the microcomputer MCB waits until an interruptionINT₀ occurs again.

If an interruption INT₀ is caused by the operation of the lightmeasuring switch S₁, it is detected at step #4 whether or not the AElock switch ALS is ON. If the terminal P₇ is "L", it is decided that theAE lock switch ALS is ON, so that the program goes to step #5 so as toset the AE lock flag ALF. If the terminal P₇ is "H" at step #4, it isdecided that the AE lock switch ALS is OFF, then the program skips tostep #6. At step #6, the CCD line sensor provided in the light receivingcircuit AFD for detecting focusing condition is initialized. At step #7,CCD integration is started and at step #8, an interruption INT₁ whichoccurs when the CCD integration has been completed is allowed.Thereafter, at step #9, the terminal P₀ is set to "L" so as to outputthe light measuring start signal LSTA, to operate the A-D converterprovided in the light measuring interface LIF so that the A-D conversionoperation is started, then the program goes to step AE routine.

When the interruption INT₀ occurs by the operation of the AE lock switchALS, the AE lock flag ALF is set at step #11. Then, the flag FIHF is setat step #12, thereafter, the program goes to AE routine.

AE routine

FIG. 5 is a flowchart showing the control to be executed in the AEroutine. In this routine, through the serial data bus SDB, at step #21,lens information is inputted from the lens circuit LEC to themicrocomputer MCB, then at step #22, flash data FCR₀ and FCR₁ areinputted from the flash circuit FLC thereto, and at step #23, an ISOsensitivity is inputted from the display circuit DSP thereto.Thereafter, at step #24, data of lights measured by the photodiodes PD₀through PD₅ are inputted from the light measuring circuit LMA to themicrocomputer MCB through the light measuring interface LIF and theserial data bus SDB. At step #25, an exposure calculation is performedusing the above-described data. A subroutine of step #24 (input luminousdata) and a subroutine of step #25 (exposure calculation) are describedlater (refer to FIGS. 12 through 24.)

After the exposure calculation is completed, at step #26, the displaydata shown in Table 4-1 are outputted to the display circuit DSP throughthe serial data bus SDB so as to display various photographing data. Atstep #27, data CFR₀ through CFR₃ are outputted to the flash circuit FLCthrough the serial data bus SDB. Then, at step #28, the flag AEF is set.Thereafter, the program goes to step #29.

It is detected at step #29 whether or not an automatic focusingoperation (hereinafter referred to as AF operation) is completed. If theflag FDF is set, it is decided that the AF operation has not beencompleted, so that the program goes to the AF routine. If the flag FDFis reset, it is decided that the AF operation has been completed, thenthe program goes to step #30. The AF routine is described in detail(refer to FIG. 9.)

At step #30, it is detected whether or not a shutter release isprohibited. If the release prohibiting flag RIHF is set, it is decidedthat the shutter release is prohibited, so that the program goes to theswitch determining routine II (FIG. 7). If the flag RIHF is reset, it isdecided that the shutter release is allowed, so that the program goes tostep #31.

It is detected at step #31 whether or not the AE lock is effected inresponse to the achievement of the in-focus state, which is describedlater. If the flag BLFF is set, it is decided that the AE lock iseffected in response to the achievement of the in-focus state, then theprogram goes to step #32. If the flag BLFF is not set, the program goesto the switch determining routine I (FIG. 6).

It is detected at step #32 whether or not the shutter release is carriedout. If the terminal P₁₂ is "L", it is decided that the release buttonis pressed to the second stroke, i.e., the switch S₂ is turned on, sothat the program goes to the subroutine "exposure control" (refer tostep #33 in FIG. 24). When a photographing has been completed, theprogram goes to the switch determining routine II (FIG. 7). If theterminal P₁₂ is "H" at step #32, it is decided that the release buttonhas not been pressed (switch S₂ is OFF), so that the program goes to theswitch determining routine I (FIG. 6).

Switch determining routine I

FIG. 6 is a flowchart showing the switch determining routine I. In thisroutine, first, at step #41, it is detected whether or not the lightmeasuring switch S₁ is turned on. If the terminal P₆ is "L", it isdecided that the switch S₁ is ON, then the program goes to step #42. Ifthe terminal P₆ is "H", it is decided that the switch S₁ is OFF, thenthe program goes to step #53.

It is detected at step #42 whether or not the focusing conditiondetecting operation is prohibited. If the flag FIHF is set, it isdecided that the focusing condition detecting operation is prohibited.Then, at step #43, the flag FIHF is reset, and the CCD integrations arestarted at step #44, and at step #45, it is enabled that the completionof the CCD integration causes the interruption INT₁. If the flag FIHF isreset at step #42, the program skips to step #46.

It is detected at step #46 whether or not the AE lock switch ALS is ONor OFF. If the terminal P₇ is "L", it is decided that the switch ALS isON, then the program goes to step #47. If the terminal P₇ is "H", it isdecided that the switch ALS is OFF, then the program goes to step #51.

At step #47, the state of the AE lock flag ALF is detected. If the AElock flag ALF is set, the program skips to step #50, and if the AE lockflag ALF is reset, the program goes to step #48. The flag ALF is set atstep #48, then a flag BLAF, showing that the AE lock has been completedby the AE lock switch ALS, is reset at step #49. Thereafter, the programgoes to step #50. At step #50, a timer is reset to start its operationand the program returns to the AE routine (FIG. 5). A light measuringoperation, an exposure calculation, and the input/output and indicationof data are kept performed until the timer counts a predetermined period(for example, 10 seconds) after both the switch S₁ and ALS are turnedoff.

If the terminal P₇ is "H" at step #46, it is decided that the switch ALSis OFF, then at steps #51 and #52, the AE lock flag ALF and the flagBLAF are reset. At step #50, the timer is reset to start its operation,then the program returns to the AE routine (FIG. 5).

If the light measuring switch S₁ is OFF at step #41, a flag FIF is resetat step #53. Thereafter, at step #54, "00" is stored in the data AFD sothat the indication showing the in-focus state is cleared. At step #55,the lens drive motor MOL is stopped and the interruption INT₁ caused bythe completion of the CCD integrations is disabled at step #56.Accordingly, if the measuring switch S₁ is OFF, a focusing conditiondetecting operation is not performed. Thereafter, the program goes tosteps subsequent to step #57 to execute the processing.

At step #57, it is detected whether the AE lock switch ALS is ON or OFF.If the terminal P₇ is "L", it is decided that the switch ALS is ON, thenthe flag FIHF is set at step #58. Thereafter, the program goes to step#59.

At step #59, the state of the AE lock flag ALF is detected. If the AElock flag ALF is reset, the AE lock flag is set at step #60, then theflag BLAF, indicating that the AE lock in response to the AE lock switchALS (hereinafter referred to as manual AE lock) is completed, is resetat step #61. Thereafter, the timer is reset to start its operation atstep #50, and then the program returns to the AE routine (FIG. 5). Onthe other hand, if the AE lock flag ALF is set at step #59, the programskips to step #50 so as to reset the timer for its operation start, thusreturning to the AE routine (FIG. 5).

If the terminal P₇ is "H" at step #57, it is decided that the AE lockswitch ALS is OFF, i.e., both the switches S₁ and ALS are OFF. Then, theprogram goes to step #62. At step #62, the flag FIHF is reset, then atstep #63, the interruption INT₀ caused by the operations either of theswitches S₁, ALS, SRS, MOS, US, and DS is allowed. Thereafter, theprogram goes to step #64. At step #64, as described above, it isdetected whether or not the timer has counted the predetermined period(approximately 10 seconds). If the counter has not counted thepredetermined period, the program returns to the AE routine so that alight measuring operation, an exposure calculation, and the input/outputand indication of data are performed. If the timer has counted thepredetermined period, the program goes to the STOP routine (FIG. 8).Then, the microcomputer MCB stops its operation until the interruptionINT₀ occurs again.

Switch determining routine II

FIG. 7 is a flowchart showing the switch determining routine II. Asapparent from the AE routine shown in FIG. 5, the microcomputer MCBprocesses the execution of this routine either when the exposure controlis effected by the press of the release button to the second stroke(step #32 to #33) or the shutter release is prohibited at step #30.

First, the flag FLF and the flag BLFF are reset at steps #71 and #72,then it is detected at step #73 whether the light measuring switch S₁ isON or OFF. If the terminal P₆ is "L", it is decided that the switch S₁is ON. Then, the program goes to step #74. At step #74, the releaseprohibiting flag RIHF is set to prohibit subsequent shutter releaseoperations, whereby even though the release button is erroneously keptpressed, a photographing operation is not performed, i.e., films are notwasted.

At step #75, it is detected whether the AE lock switch ALS is ON or OFF.If the terminal P₇ is "L", it is decided that the switch ALS is ON.Then, the program goes to step #76. If the terminal P₇ is "H", it isdecided that the switch ALS is OFF, and then the program goes to step#79.

At step #76, the state of the AE lock flag ALF is detected. If the flagALF is set, the program returns to the AE routine (FIG. 5). On the otherhand, if the flag ALF is reset, the flag ALF is set at step #77. Then,the flag BLAF is reset at step #78, and thereafter, the program returnsto the AE routine (FIG. 5).

If the program goes to step #79 after it is decided at step #75 that theAE lock switch ALS is OFF, the AE lock flag ALF and the flag BLAF arereset at steps #79 and #80. Thereafter, the program returns to the AEroutine (FIG. 5).

At step #73, if the terminal P₆ is "H", it is decided that the lightmeasuring switch S₁ is OFF, then, at step #81, "00" is stored in thedata AFD to clear the indication showing that the in-focus state hasbeen obtained. Then, the release prohibiting flag RIHF is reset at step#82, and subsequent shutter release operations are allowed, and then theprogram goes to step #83.

At step #83, the ON or OFF of the AE lock switch ALS is detected. If theterminal P₇ is "L", it is decided that the switch ALS is ON, then theflag FIHF is set at step #84. Thereafter, the program goes to step #85.If the terminal P₇ is "H", it is decided that the switch ALS is OFF, andthe flag FIHF is reset at step #88. Thereafter, the program goes to theSTOP routine (FIG. 8).

At step #85, the state of the AE lock flag ALF is detected. If the flagALF is set, the program returns to the AE routine (FIG. 5). On the otherhand, if the flag ALF is reset, the flag ALF is set at step #86 and theflag BLAF is reset at step #87. Then, the program returns to the AEroutine (FIG. 5).

There is a case in which the AE lock switch ALS is turned on during theprocessings of the AE routine, the switch determining routine I, and theswitch determining routine II. There is also a case in which after theAE lock switch ALS is turned off to unlock the AE lock, and then, the AElock switch ALS is turned on to perform the AE lock. Under the AE lockmode, it is necessary to lock the value of a light measured at the timewhen the AE lock switch ALS is turned on. In this camera system, whenthe above-described two cases are detected (steps #47, #58, #76, #85),the flag BLAF indicating that the manual AE lock has been completed isreset (steps #49, #60, #78, #87) to lock a value of a light measuredimmediately after the flag BLAF is reset. Accordingly, the AE lock canbe accurately performed in the above-described two cases.

STOP routine

FIG. 8 is a flowchart showing the STOP routine. In this routine, thedata FCR₀ and FCR₁ are transmitted from the flash circuit FLC to themicrocomputer MCB at step #91.

Next, the exposure control mode of the camera system is detected. Firstof all, it is detected whether or not the exposure control mode is (M)mode at step #92. If the content of the exposure control register MOR is"11", it is decided that the exposure control mode is (M) mode. Then,the program skips to step #97. If it is decided at step #92 that theexposure control mode is not (M) mode, it is then detected at step #93whether the exposure control mode is (S) mode or not. If the content ofthe register MOR is "01", it is decided that the exposure control modeis (S) mode. Then, the program skips to step #96. If it is decided atstep #93 that the exposure control mode is not (S) mode (that is, if itis decided that the exposure control mode is neither (M) mode nor (S)mode), at step #94, a blank indication data BLD is stored in anindication data TVD to clear the indication of the control exposure timeTv. It is detected at step #95 whether or not the exposure control modeis (A) mode. If the content of the register MOR is "10", it is decidedthat the exposure control mode is (A) mode. Then, the program skips tostep #97. If it is decided at step #95 that the exposure control mode isnot (A) mode, that is, if it is decided that the exposure control modeis (P) mode, the blank indication data BLD is stored in the indicationdata AVD to clear the control aperture value Av. Thereafter, the programgoes to step #97.

The summary of step #92 through step #96 is as follows: If the exposurecontrol mode is (P) mode, the indications of the control aperture valueAv and the control exposure time Tv are cleared. If the exposure controlmode is (S) mode, the indication of the control aperture value Av iscleared. If the exposure control mode is (A) mode, the indication of thecontrol exposure time Tv is cleared. If the exposure control mode is (M)mode, the indications of the control aperture value Av and the controlexposure time Tv are not cleared. Accordingly, only the aperture valueAvs and exposure time Tvs both manually set are indicated, and thecalculated aperture value Av and the calculated exposure time Tv are notindicated.

At step #97, "0" is stored in the indication data ALD so as to clear theindication that the AE lock is being carried out. Then, at step #98,"00" is stored in the indication data AFD to clear the indication thatthe in-focus state has been obtained.

At step #99, it is detected whether or not the flash stopping signalFSTP is outputted from the flash circuit FLC. If the fifth bit FCR₀₄ ofthe data FCR₀ outputted from the flash circuit FLC is "1", it is decidedthat the flash stopping signal FSTP is outputted therefrom. Then, theprogram goes to step #100. At step #100, "10" is stored in theindication data FLD₁ so as to indicate that the flash light has beencorrectly emitted, then at step #101, "00" is stored in the indicationdata FLD₂ so as to clear the indication showing other flash information.Then, at step #102, the indication data are outputted from themicrocomputer MCB to the display circuit DSP. Upon receipt of theindication data, the display circuit DSP displays the information of thedata. Thereafter, the microcomputer MCB executes the processing fromstep #91.

If the fifth bit FCR₀₄ of the data FCR₀ outputted from the flash circuitFLC is "0" at step #99, it is decided that the flash stopping signalFSTP is not outputted therefrom. At step #103, "00" is stored in theindication data FLD₁ and FLD₂ to clear the indications of all the flashinformation. Then at step #104, the seventh bit CFR₃₆ of the data CFR₃is set to stop the display circuit FDP and the indicator CHD provided inthe flash circuit FLC from making indications.

Thereafter, at step #105, the microcomputer MCB outputs the indicationdata to the display circuit DSP through the serial data bus SDB andoutputs the flash data CFR₀ through CFR₃ to the flash circuit FLC atstep #106, whereby the information of the indication data is indicatedby the display circuit DSP and the operations of the display circuit FDPand the indicator CHD provided in the flash circuit FLC are stopped.

Thereafter, at step #107, an "H" level signal is outputted (hereinafterreferred to as "H" or "L" is outputted) from the terminal P₀ so as toclear the A-D conversion start signal LSTA, and to stop the operation ofthe A-D converter provided in the light measuring interface LIF. Afterall the flags are reset at step #108, "H" is outputted, at step #109,from the power control terminal P₅ to stop the operation of the DC-to-DCconverter VG, which stops the operations of the AF interface AIF, thelight receiving circuit AFD for detecting focusing condition, the lightmeasuring interface LIF, the light measuring circuit LMA, the flashlight measuring circuit LMF, the lens circuit LEC, the drive circuitDDR, and the encoders ENAP and the ENLE. Thereafter, at step #110, themicrocomputer MCB allows the interruption INT₀, and at step #111, theoutput of the reference clock STCK and the operation of the referenceclock generating circuit XB are stopped. Then, the microcomputer MCBwaits until the interruption INT₀ is caused again by either of theswitches S₁, ALS, SRS, MOS, US, and DS.

Interruption INT₁

FIG. 9 is a flowchart showing the processing to be executed after theinterruption INT₁ occurs due to the completion of the CCD integration ofthe line sensors ISL₀, ISL₁, ISL₂ provided in the light receivingcircuit AFD for detecting focusing condition.

As previously described, upon completion of the CCD integration of theline sensors ISL₀, ISL₁, ISL₂, the AF interface AIF outputs an "L" levelsignal indicative of an integration completion to the terminal INT₁ ofthe microcomputer MCB, whereby the microcomputer MCB operates accordingto the flowchart shown in FIG. 9.

First, at step #1001, it is detected whether or not an exposurecalculation is completed. If the flag AEF is set, it is decided that theexposure calculation is completed, then the program goes to step #121(AF routine). If the flag AEF is reset, it is decided that the exposurecalculation has not yet been completed, then the program goes to step#1002. At step #1002, the flag FDF is set and then the program returnsto the step at which the processing is executed when the interruptionINT₁ occurs. This is to perform the operation for an exposure controland make a data indication. After light measuring, calculations, andindication operations are performed, the program immediately returns tothe AF routine (see step #29 in FIG. 5).

AF routine

Next, the AF routine is described hereinbelow.

First, the flag FDF is reset at step #121. Thereafter, at step #122, thedata of the pixels of the CCD line sensors ISL₀, ISL₁, and ISL₂ areinputted to the microcomputer MCB. Based on these data, the detection ofthe in-focus states of the zero zone, the first zone, and the secondzone and the detection of a defocus direction, and the calculation ofthe defocus amount are performed at steps #123, #124, and #125. Then itis examined at step #126 whether or not it is possible to detectfocusing condition. If the detection of the focusing condition ispossible in at least one of the three zones, the program goes to step#133. If it is impossible to detect the focusing condition in any one ofthe three zones, the program goes to step #127.

At step #127, it is detected whether or not a low contrast search hasbeen effected. If the flag DDEF is reset, it is decided that the lowcontrast search has not been carried out. Then, the program goes to step#132 so as to carry out a low contrast search. On the other hand, if theflag DDEF is set, it is decided that the low contrast search iscompleted. Then, the program goes to step #129. At step #129, the CCDintegrations are resumed, and the interruption INT₁ is allowed at step#130. Then at step #131, "10" is stored in the indication data AFD towarn the photographer that it is impossible to detect focusingcondition. Then, the program goes to AE routine (FIG. 5). Accordingly,once the low contrast search is made, no low contrast search areperformed any more. When the low contrast search is carried out at step#132, the program goes to the AE routine when the low contrast searchhas been completed.

At step #126, if the program goes to step #133 because there is a zonewhere focusing condition can be detected, it is detected whether or notthe low contrast search is being performed. If the low contrast flag LCFis reset, it is decided that the low contrast search is not beingperformed, so that the program goes to the in-focus detection routine(FIG. 10). If the flag LCF is set at step #133, it is decided that thelow contrast search is being performed. Then, the program goes to step#134.

At step #134, the lens drive motor MOL is stopped, and the low contrastflag LCF is reset at step #135. As described later, the lens is movingduring the low contrast search. Therefore, when the lens drive motor MOLis stopped at step #134, the in-focus state, the defocus direction, anddefocus amount found according to the pixels of the CCD line sensorsISL₀, ISL₁, ISL₂ do not correspond to the actual lens position, so thatthe above-described data are not reliable. Therefore, at step #136, theCCD integrations are resumed with the lens postion fixed and theinterruption INT₁ is allowed at step #137. Then, the program goes to theAE routine so that the pixel data outputted from the CCD line sensorscan be obtained. If a warning indicating that a focusing conditioncannot be detected is indicated, at step #138, "00" is stored in theindication data AFD to clear the warning indication. Then, the programgoes to the AE routine (FIG. 5).

In-focus detection and interruption CNT

FIG. 10 is a flowchart showing the in-focus detection routine and theprocessing to be executed when the counter interruption CNT occurs. Inthe in-focus detection routine, focusing condition detecting operationsand in-focus determining operations are performed.

When the program goes to the in-focus detection routine, at step #141, azone for focusing (hereinafter referred to as main zone) is selectedfrom the zero through the second zone. In principle, a zone in which anobject nearest the photographing lens is disposed (a zone in which theamount of a rear focus is maximum) is selected as the main zone.Needless to say, if there is only one zone where focusing condition canbe detected, the zone is adopted as the main zone. The method forselecting a zone is disclosed in U.S. Pat. application Ser. No. 196,254the present applicant previously proposed.

Thereafter, it is detected at step #142 whether or not zones except themain zone are adjacent zones. That is, it is detected whether or notthere are objects (hereinafter referred to as adjacent object) which areclose to the object (hereinafter referred to as main object) located inthe main zone selected at step #141. The adjacent object herein means inprinciple the same object as the main object. If the defocus amount ofan object with respect to the main object is less than a predeterminedvalue (80 μm in this embodiment), it is decided that the object is anadjacent object.

Specifically, in a portrait (photographing magnification β=1/10) inwhich a face is photographed as large as possible, if the difference ofphotographing distance between two objects is less than 2 cm (about theheight of the nose), it is decided that the objects are adjacentobjects. In a portrait (β=1/4) in which a person is photographedwidthwise from his face to waist, if the difference of photographingdistance between two objects is less than 14 cm (about the heightbetween the top of the nose and the ear), it is decided that the objectsare adjacent objects. In a photograph (photographing magnificationβ=1/100) in which several men are photographed, if the difference ofphotographing distance between two objects is less than 95 cm (aboutdepth between a person's face in the front row and a person's face inthe rear row), it is decided that objects located in this range areadjacent objects.

The microcomputer MCB stores the data of the main zone and the adjacentzone(s) in which adjacent objects are present, and as described later,selects a light measuring calculation based on these data.

Next, at step #143, it is decided whether or not the object imagelocated within the main zone selected at step #141 is in focus. If theobject image is not in focus, at step #144, a lens movement amount iscalculated according to the defocus amount. Thereafter, thephotographing distance (D) as well as the photographing magnification βare calculated at steps #145 and #146.

The methods for calculating the photographing distance (D) and thephotographing magnification β are described hereinbelow.

Assuming that the lens drive amount is N and the defocus amount is DF,the following relationship is established.

    N=K×DF                                               (1)

where K is a constant called a conversion coefficient, which variesdepending on lenses. The conversion coefficient (K) is outputted fromthe lens drive circuit LEC to the microcomputer MCB. The conversioncoefficient (K) is described in detail, for example, in Japanese PatentLaid-Open Publication No. 142528/1984. The photographing distance D₀ isexpressed as follows, which is well known.

    D.sub.0 =k/n.sub.0                                         (2)

    k=a·f.sup.2                                       (3)

n₀ : lens movement amount from a position in which a lens is focused onthe infinite point

f: focal length of lens

a: constant.

The constant (k) and the focal length (f) of the lens are inputted fromthe lens circuit LEC to the microcomputer MCB. Accordingly, assumingthat the photographing distance calculated when a focusing condition isdetected is D₁, its apex value is Dv₁ (inputted from the lens circuitLEC), and the lens movement amount from the position in which the lensis focused on the infinite point to the present position is n₁, thefollowing relationship is established:

    Dv.sub.1 =2log.sub.2 D.sub.1                               (4)

    D.sub.1 =k/n.sub.1                                         (5).

The lens movement amount to focus is expressed by the equation (1).Accordingly, the lens movement amount n₂ from the position at which thelens is focused on the infinite point to the in-focus position isexpressed as follows:

    n.sub.2 =n.sub.1 ±N                                     (6)

where (+) of (±) means a front focus and (-) means a rear focus.Accordingly, the photographing distance (D) at the in-focus position,namely, the photographing distance (D) of the main object is expressedas follows from the equation (2):

    D=k/n.sub.2                                                (7)

The apex value Dv is expressed as follows similarly to the equation (4):

    Dv=2log.sub.2 D                                            (8).

The photographing magnification β can be found from the followingequation:

    β=f/D                                                 (9).

Thereafter, the pulse number (N) corresponding to the lens movementamount found at step #144 is set to an event counter at step #147 andthe counter interruption CNT is allowed at step #148. As describedlater, since "L" is outputted from the terminal P₁₅, the pulse outputtedfrom the encoder ENLE can be inputted to the terminal CNT. Themicrocomputer MCB transmits data to the drive circuit DDR at step #149,the circuit DDR drives the lens drive motor MOL to drive the lens.Thereafter, the program returns to the step at which the interruptionINT₁ occurs. If it is decided at step #29 in the AE routine (FIG. 5)that the AF operation has not been completed and then the program goesto AF routine, the program returns to the AE routine, and theprocessings are executed from step #21.

In a camera system in which only the constant (k) is inputted from thelens circuit LEC and the photographing distance Dv at the time whenfocus condition is detected is not inputted, as described in JapanesePatent Laid-Open Publication No. 150921/1983, a counter for monitoringthe lens movement amount from the position at which the lens is focusedon the infinite point to the present position may be provided so thatthe lens movement amount n₂ =n₁ ±N (where n₁ means the present countvalue of the counter) from a position at which the lens is focused onthe infinite point to the in-focus position is found and thephotographing distance (D) of the main object is found based on the lensdrive amount n₂.

When it is decided at step #143 that an object image located in the mainzone is focused, i.e., when it is decided that the defocus amount of anobject located in the main zone is less than a predetermined value (forexample, 30 μm), the program goes to step #150, and "01" is stored inthe indication data AFD to make the display circuit DSP display that thein-focus state is obtained. Thereafter, the microcomputer MCB calculatesat step #151 the photographing magnification β based on the distanceinformation (D) outputted from the lens circuit LEC when focusingcondition is detected (or the distance information D₁ calculatedaccording to the lens movement amount n₁ from the position at which thelens is focused on the infinite point to the position where focusingcondition is detected and the constant (k)) and the information of thefocal length (f). Then, the focus lock flag FLF is set at step #152, andthe program goes to the AE routine (FIG. 5). Therefore, if an in-focusstate is obtained, the CCD integrations are not performed any longer andmicrocomputer MCB does not allow the interruption INT₁, so that theprogram goes to the AE routine.

Next, the counter interruption CNT is described hereinbelow.

When the number of pulses, inputted to the terminal CNT, counted by theevent counter provided in the microcomputer MCB has reached apredetermined number, the event counter causes an interruption CNT,whereby processing is executed from step #161. First, it is decidedwhether the interruption CNT is caused during the stopping down or whilethe AF operation is being carried out. That is, it is detected whetherthe pulse inputted to the terminal CNT is outputted from the encoderENAP or the encoder ENLE.

If the terminal P₁₅ is "H", it is decided that the pulse is outputtedfrom the encoder ENAP, i.e., the stopping down operation is beingperformed, then the program goes to step #166 at which data istransferred to the drive circuit DDR so that the magnets APM arerepelled, whereby the stopping down operation is stopped. Then, theprogram returns to the step at which the processing is executed when theinterruption CNT occurs.

If the terminal P₁₅ is "L", it is decided that the pulse is outputtedfrom the encoder ENLE, that is, it is decided that the AF operation isbeing performed. Then the program goes to step #162 at which data istransferred to the drive circuit DDR to stop the lens drive motor MOL.Thereafter, the program goes to step #163.

It is decided at step #163 whether or not the lens movement amount (N)is greater than the predetermined value N₀. If the lens movement amount(N) is larger, it means that when a defocus amount is calculated at step#144, the defocus amount is large, which causes the image to be blurred.Accordingly, there is a possibility that the defocus amount measured inthis case includes an error, so that this amount is not reliable. Inorder to overcome this problem, according to the embodiment, if the lensmovement amount (N) is greater than the predetermined value N₀, the CCDintegrations are resumed at step #164 and the interruption INT₁ isenabled at step #165 so that it is confirmed whether or not an in-focusstate is obtained, whereby the AF accuracy can be improved. After theinterruption INT₁ is allowed at step #165, the program returns to thestep at which the processing of the interruption CNT occurs.

If it is decided at step #163 that the lens movement amount (N) is lessthan or equal to the predetermined value N₀, the program goes to step#150 without checking the in-focus state by deciding that there is noerror in the calculated defocus amount, namely, it is reliable, and thenabove-described processings (step #150 through #152) are performed.Then, the program goes to the AE routine (FIG. 5).

As previously described, when the in-focus state is obtained, theprogram goes to the AE routine without performing the CCD integrationsand allowing the interruption INT₁. Therefore, the program no longergoes to the AF routine (FIG. 9). That is, once the in-focus state isobtained, the AF operation is not performed until the interruption INT₁is allowed at step #8 after the interruption INT₀ occurs with the lightmeasuring switch S₁ turned off, then turned on, and the CCD integrationsare started at step #7. In other words, a so-called focus lock iseffected with the light measuring switch S₁ being ON. That is, accordingto the camera system of the embodiment, a one-shot AF operation isaccomplished.

Low contrast search

FIG. 11 is a flowchart showing the subroutine "low contrast search". Inthis subroutine, it is decided at step #171 whether or not a lowcontrast search is being executed. If the low contrast flag LCF isreset, it is decided that the low contrast search has not been carriedout, then the program goes to step #172. Thereafter, the flag LCF isset, then data is outputted to the drive circuit DDR to drive the lensdrive motor MOL, whereby the low contrast search operation is started atstep #173. On the other hand, if the flag LCF is set at step #171, it isdecided that the low contrast search is being executed, then the programskips to step #174.

At step #174, the CCD integrations are started, and at step #175, theinterruption INT₁ is allowed due to the completion of the CCDintegrations.

Thereafter, it is decided at step #176 whether or not the lens hasreached the end of its movable range. This decision is made by detectingwhether or not a pulse is inputted to the terminal CNT within a certainperiod. When the lens reaches the end of its movable range, the lens isnot allowed to move further. Therefore, a pulse is not outputted fromthe encoder ENLE, i.e., if a pulse is not inputted to the terminal CNTwithin a certain period, it is decided that the lens has reached the endof its movable range. A switch which is turned on or off when the lenshas reached the end of its movable range may be provided according towhich it can be detected whether or not the lens has reached the end ofits movable range.

If it is decided at step #176 that the lens has not reached the end ofits movable range, the program goes to step #181 at which the ON or OFFof the light measuring switch S₁ is checked. If "L" is inputted to theterminal P₆, it is decided that the switch S₁ is ON, then the programreturns to step #176. If "H" is inputted to the terminal P₆, it isdecided that the switch S₁ is OFF. Then, the program goes to step #180.

If it is decided at step #176 that the lens has reached the end of itsmovable range, the program goes to step #177. At step S177, it isdetected whether or not the lens has moved the end of its movable rangeeither once or twice. If it is detected that the lens has reached theend of its movable range for the first time, the program goes to step#182 at which data is outputted to the drive circuit DDR so as to rotatethe lens drive motor MOL reversely. Then, the program returns to step#176 so that the low contrast search is performed in the reversedirection. If it is decided at step #177 that the lens has reached theend of its movable range for the second time, data is outputted to thedrive circuit DDR to stop the lens drive motor MOL at step #178.

The above-described operation is briefly described as follows: The lowcontrast search is executed with the lens moved in a direction (forexample, to the closest direction) from the current position. If anin-focus position cannot be detected before the lens reaches the end ofits movable range, the lens is moved in the opposite direction (forexample, distant direction) so as to execute the low contrast search ofthe region between the initial position and the other end (for example,the position at which the lens is focused on the infinity point),whereby the low contrast search can be executed in the entire themovable range. If, as a result of the low contrast search, the lensreaches the other end (for example, the position at which the lens isfocused on the infinity point) of its movable range without obtaining aposition at which focusing condition can be detected, the lens isstopped from being driven and the low contrast search is terminated.

When the lens drive motor is stopped at step #178, the flag DDEF is setat step #179 so as to memorize that the low contrast search has beenmade, and a low contrast flag LCF is reset at step #180 as so toindicate that the low contrast search has not been executed. Then, theprogram returns to the AF routine (FIG. 9).

Subroutine in AE routine

Next, the subroutine (FIG. 12 through FIG. 24) in the AE routine aredescribed hereinbelow.

Input of luminous data

FIG. 12 is a flowchart showing the subroutine "input of luminous data"(step #24) in the AE routine. In this subroutine, values of measuredlights which have entered the photodiodes PD₀ through PD₅ are inputtedto the input/output terminal SIO₀ of the microcomputer MCB through thelight measuring interface LIF and the serial data bus SDB, and thevalues of the measured lights are stored in three registers FLR, NMR,and ALR according to the state (for example, AE lock) when it isinputted to the microcomputer MCB.

First, it is detected at step #201 whether or not the AE lock switch ALSis ON. If the AE lock flag ALF is set, it is decided at that the AE lockswitch ALS is ON, then the program goes to step #207. If the flag ALF isreset, it is decided that the AE lock switch ALS is not ON, then theprogram goes to step #202. If the flag BLAF is set at step #207, it isdecided that the AE lock is completed, and the program goes to step#202. It is detected at step #202 whether or not a focus lock iscompleted. If the focus lock flag FLF is set, it is decided that thefocus lock is completed, so that the program goes to step #203. If thefocus lock flag FLF is reset, it is decided that the focus lock is notcompleted, then the program goes to step #206.

It is detected at step #203 whether or not the AE lock, which isperformed when the in-focus state is detected, is completed. If the flagBLFF is set, it is decided that the AE lock, which is performed when thein-focus state is detected, is completed. Then, the program goes to step#206. If the flag BLFF is reset, it is decided that the AE lock is notcompleted, then the program goes to step #204.

At step #204, the flag BLFF is set to indicate that the AE lock, whichis performed when the in-focus state is detected, is completed and thevalues of measured lights are stored in the focus AE lock register FLR,then the program returns to the AE routine (step #25 in FIG. 5).

At step #206, the measured values of the lights are stored in a normalregister NMR, then the program returns to the AE routine (step #25 inFIG. 5).

If it is decided at step #207 that AE lock is not completed by the AElock switch ALS, the program goes to step #208 at which the flag BLAF isset to indicate that the manual AE lock is completed and the values ofthe measured lights are stored in the AE lock register ALR. Then, theprogram returns to AE routine (step #25 in FIG. 5).

In these circumstances, the data of measured light is stored in theregister ALR immediately after the AE lock switch is turned on, in theregister FLR immediately after in-focus condition is obtained, and inthe register NMR at other times.

Exposure calculation

FIGS. 13a and 13b are flowcharts showing the subroutine "exposurecalculation" (step #25) in the AE routine (FIG. 5).

In this subroutine, first, it is detected at step #221 whether or notthe manual AE lock is made. If the flag BLAF is set, it is decided thatthe manual AE lock is executed, then the program goes to step #222 atwhich the values of the measured lights stored in the AE lock registerALR are stored in six registers Bv0 through Bv5. The registers Bv0through Bv5, respectively, stored the values of the light measured bythe photodiodes PD₀ through PD₅.

On the other hand, at step #221, if the flag BLAF is reset, it isdecided that the manual AE lock is not executed, so that the programgoes to step #224. It is detected at step #224 whether or not the AElock, which is performed when the in-focus state is detected, iscompleted. If the flag BLFF is set, it is decided that the AE lock isexecuted, then the program goes to step #225 at which the measured lightvalues stored in the focus AE lock register FLR are stored in theregisters Bv0 through Bv5. If the flag BLFF is reset, it is decided thatthe AE lock, which is performed when the in-focus state is detected, isnot executed, so that the program goes to step #226 at which themeasured light values stored in the normal register NMR are stored inthe registers Bv0 through Bv5.

When the measured light values are stored in the registers Bv0 throughBv5, the microcomputer MCB corrects measured light values at step #223on the light receiving area and optical characteristics of thephotodiodes PD₀ through PD₅, the minimum (open) aperture value, an errorin luminance measured according to the minimum aperture value (these twovalues are inputted from the lens circuit LEC.)

As apparent from the foregoing description, according to the camerasystem in accordance with the embodiment, the manual AE lock is executedprior to other operations.

After the measured light values Bv0 through Bv5 are corrected, it isdetected at step #227 whether or not the manual AE lock is executed. Ifit is decided that the flag BLAF is set, that is, the manual AE lock isexecuted, the program goes to step #228. At step #228, the emission modeof the flash emitting device is detected and if it is decided that thehigh-order two bits FCR₀₇ and FCR₀₈ of the data FCR₀ are not "00", i.e.,if the flash emitting device is not set to the forced emission mode, theprogram goes to the subroutine "spot light measuring" (step #259).

If it is decided at at step #227 that the manual AE lock is notperformed or that the emission mode of the flash device is the forcedemission mode at step #228, the processings are executed at stepssubsequent to step #230. That is, only when the manual AE lock isexecuted and the flash emission mode is not the forced emission mode,the program goes to the subroutine "spot light measuring".

As described later, since the forced emission mode is not executed in(P) mode, the spot light measuring can be obtained by operating the AElock switch ALS in (P) mode.

It is decided at step #230 whether or not the photographingmagnification β is calculated. If the photographing magnification β iscalculated, the program goes to step #231 at which a predeterminedcalculation is performed according to the photographing magnification βand the focal length (f) of the photographing lens so as to calculatethe luminance Bvs of the main object and the luminance Bva of thebackground. If the photographing magnification β is not calculated, theprogram goes to step #242 so as to calculate the luminance Bvs of a mainobject and the luminance Bva of the background.

The program may go from step #230 to #242 only when the photographinglens is not mounted on the camera assuming that the photographingmagnification β is 1/60 until the photographing magnification β iscalculated at step #151 of the in-focus detection routine (FIG. 10). Atthis time, it is detected whether or not the photographing lens ismounted on the camera according to the data outputted from the lenscircuit LEC.

At step #231, the photographing magnification β is compared with apredetermined magnification β₂ (for example, 1/40). If β>β₂, the programgoes to step #232 at which "Bvs calculation I" is performed to calculatethe luminance Bvs of the main object. As described later, in the "Bvscalculation I", the luminance Bvs is calculated on five data of themeasured light values of Bv0 through Bv4. Therefore, the luminance Bvaof the background can be calculated on the measured light value Bvs atstep #233.

If β≦β₂ at step #231, the program goes to step #234 at which thephotographing magnification β is compared with a predeterminedmagnification β₁ (β₁ <β₂, for example, 1/60). If β>β₁ (that is, β₁<β<β₂), the program goes to step #235. At step #235, the focal length(f) of the photographing lens is compared with a predetermined focallength (f₁) (for example 28 mm). If f>f₁, the program goes step #236 atwhich "Bvs calculation II" is performed to calculate the luminance Bvsof the main object. As described later, in the "Bvs calculation II", theluminance Bvs of the main object is calculated on three measured lightvalues Bv0 through Bv2. Accordingly, the luminance Bva of the backgroundcan be calculated at step #237 on the measured light values Bv3 throughBv5. If f≦f₁ at step #235, the program goes to step #242.

If β≦β₁ at step #234, the program goes to step #238 at which thephotographing magnification β is compared with a predeterminedphotographing magnification β₀ (β₀ <β₁ <β₂, for example, 1/100). If β>β₀(namely, β₀ <β<β₁), the program goes to step #239. At step #239, thefocal length (f) of the photographing lens is compared with apredetermined focal length f₀ (f₀ >f₁, for example, 50 mm). If f>f₀, theprogram goes to step #240 at which the "Bvs calculation III" isperformed to calculate the luminance Bvs of the main object. Asdescribed later, in the "Bvs calculation III", the luminance Bvs iscalculated on three measured light data Bv0 through Bv2. Therefore, theluminance Bva of the background can be calculated on the measured lightvalues Bv3 through Bv5 at step #241.

If β≦β₀ at step #238 or f≦f₀ at step #239, the program goes to step#242. At step #242, the luminance Bvs of the main object is calculatedon all the measured light values Bv0 through Bv5, and similarly theluminance Bva of the background is calculated on all the measured valuesBv0 through Bv5 at step #243. That is, an average light measuring iscarried out at steps #242 and #243.

In "Bvs calculation I", "Bvs calculation II", and "Bvs calculation III",as described later, the luminance Bvs of the main object is calculatedby performing a weighted mean with predetermined weights (refer to Table7 through 9) applied to the respective measured values Bv0 through Bv4,but the luminance Bva of the background and the luminance Bvs of themain object to be calculated at step #242 are calculated by anarithmetic mean. That is, at step #233,

    Bva=Bvs,

at steps #237 and #241,

    Bva=(Bv3+Bv4+Bv5)/3,

at step #242,

    Bvs=(Bvo+Bv1+Bv2+Bv3+Bv4+Bv5)/6,

at step #243,

    Bva=(Bv0+Bv1+Bv2+Bv3+Bv4+Bv5)/6.

                  TABLE 7                                                         ______________________________________                                        first zone      zero zone second zone                                         ______________________________________                                        Bv0    2            2         2                                               Bv1    2            2         1                                               Bv2    1            2         2                                               Bv3    1            1         1                                               Bv4    1            1         1                                               ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        first zone                  second zone                                       0 far       0 near  zero zone   0 near                                                                              0 far                                   ______________________________________                                        Bv0   1         2       2         2     1                                     Bv1   2         2       1         1     0                                     Bv2   0         1       1         2     2                                     ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        first zone    zero zone     second zone                                       0 n           1 n      1 f      0 n                                           0 f     2 n    2 f    2 n  2 f 2 n  2 f 1 f  1 n  0 f                         ______________________________________                                        Bv0  0      1      1    1    1   1    1   1    1    0                         Bv2  1      1      1    1    1   0    0   0    1    0                         Bv2  0      1      0    1    0   1    0   1    1    1                         ______________________________________                                         f: far, n: near                                                               i far: object in (i) zone is far from main object                             i near: object in (i) zone is near main object                                (i = 0, 1, 2)                                                            

The method for calculating the luminance Bvs of the main objectaccording to the photographing magnification β and the focal length (f)of the photographing lens is shown in Table 6. In Table 6, "Bvscalculation IV" shows the calculation to be performed at step #242.

                  TABLE 6                                                         ______________________________________                                        photographing magnification β                                                      β.sub.0 β.sub.1 .sub.2                                    ______________________________________                                        focal       IV           IV         IV         I                              length                                                                              f.sub.1                                                                             IV           IV         II         I                                    f.sub.0                                                                             IV           III        II         I                              ______________________________________                                         I: Bvs operation I                                                            II: Bvs operation II                                                          III: Bvs operation III                                                        IV: Bvs operation IV                                                     

After the luminance Bvs of the main object and the luminance Bva of thebackground are calculated, the program goes to steps #251 through #258at which the exposure control values such as the shutter speed Tv theaperture value Av, and the flash emission amount Iv are calculateddepending on the luminances Bvs and Bva in accordance with thepredetermined calculation.

First, it is decided at step #251 whether or not the manual AE lock isaccomplished. If the flag BLAF is set, it is decided that the manual AElock is executed, so that the program goes to the subroutine "slowsynchronized photographing" (step #252). If the flag BLAF is reset, itis decided that the manual AE lock is not effected, then the programgoes to step #253. It is detected at step #253 whether or not theexposure control mode is (P) mode. If the content of the exposurecontrol mode register MOR is "00", it is decided that the exposurecontrol mode is (P) mode, so that the program goes to step #254. If thecontent of the exposure control mode register MOR is not "00", it isdecided that the exposure control mode is not (P) mode, then the programgoes to step #257. It is detected at step #254 whether or not the flashemission mode is the automatic emission mode. That is, if the content ofthe emission mode register FMR is "01", it is decided that the flashemitting device is set to the automatic emission mode, so that theprogram goes to the subroutine "automatic emission" (step #255). If itis not "01", the program goes to the subroutine "available light" (step#256). It is decided at step #257 whether or not the flash emission modeis the forced emission mode. That is, if the content of the emissionmode register FMR is "00", it is detected that the flash emitting deviceis set to the forced emission, so that the program goes to thesubroutine "forced emission" (#258). If not, the program goes to thesubroutine "available light" (step #256).

In the subroutines of "slow synchronized photographing", "availablelight", "automatic emission", forced emission", and "spot lightmeasuring", the exposure control value is calculated according to therespective calculation method, then the program returns to the AEroutine (step #27 in FIG. 5).

As described above, the program goes to the subroutine "slowsynchronized photographing" only when the manual AE lock is performedand the flash emission mode is the forced emission mode. When theexposure control mode is (P) mode, the program goes either to thesubroutine "automatic emission" or to the subroutine "available light"and under the other exposure control modes, the program goes either tothe subroutine of "available light" or to "forced emission".

Bvs calculation

FIG. 14 is a flowchart showing the subroutine "Bvs calculation I". Inthis routine, the luminance Bvs of the main object is calculated by theweighted mean with weights in Table 7 applied to five measured lightdata Bv0 through Bv4.

In this routine, first, it is decided which of the focusing conditiondetecting zones 0 through 2 is the main zone. That is, it is detected atsteps #261 and #262 which zone is selected at step #141 in the in-focusdetection routine (FIG. 10). If it is decided at step #261 that zerozone is the main zone, the program goes to step #263. If it is decidedat step #262 that the first zone is the main zone, the program goes tostep #264. If it is decided that neither the zero zone nor the firstzone is the main zone, that is, if it is decided that the second zone isthe main zone, the program goes to step #265.

As previously described, if the photographing magnification β is greaterthan the predetermined magnification β₂ (1/40 in this embodiment), forexample in "bust shot", the "Bvs calculation I" is processed. Therefore,when the processing of this routine is executed, it is supposed thatlights reflected from the main object are incident on most part of thelight measuring range LMR (refer to FIG. 2). Accordingly, in this case,the weight of the value of the lights obtained in the light measuringregion in the vicinity of the main zone is made to be great and theweights of the measured values of the other light measuring regions aremade to be small so as to calculate a weighted mean, which is theluminance Bvs of the main object (the measured value Bv5 of the mostouter frame is used to calculate the luminance Bva of the background).

Specifically describing, as shown in Table 7, when the main object islocated in the center (zero zone) of the photographing image plane, thatis, when the zero zone is the main zone, the luminance Bvs of the mainobject is calculated by the weighted mean with the weights of themeasured light values Bv0, Bv1, and Bv2 of the regions 1, 2, and 3 inthe light measuring region LMR in FIG. 2 being 2, and the weights of themeasured light values Bv3 and Bv4 of the regions 4 and 5 in the lightmeasuring region LMR in FIG. 2 being 1 (at step #263). That is, ##EQU1##

On the other hand, when the main object is located to the left (firstzone) to some degree with respect to the center, that is, when the firstzone is the main zone, the luminance Bvs of the main object iscalculated at step #264 by a weighted mean with the weights of themeasured light values Bv0 and Bv1 in the regions 1 and 2 being 2 andwith the measured values Bv2, Bv3, and Bv4 in the regions 3, 4, and 5being 1. That is, ##EQU2##

When the main object is located right (second zone) to some extent withrespect to the center, i.e., when the second zone is the main zone, theluminance Bvs of the main object is calculated in the manner similar tothe above (step #265). That is, ##EQU3##

When the luminance Bvs of the main object is calculated, the programreturns to the subroutine "exposure calculation" (step #233 in FIG. 13).

FIG. 15 is a flowchart showing the subroutine "Bvs calculation II". Inthis subroutine, the luminance Bvs of the main object is calculated bythe weighted mean with weights applied to three measured light valuesBv0, Bv1, and Bv2 shown in Table 8.

In this subroutine, similarly to the "Bvs calculation I", first, it isdecided at steps #271 and #272 which of the zero through second zones isthe main zone. If it is decided at step #271 that the zero zone is themain zone, the program goes to step #275. If it is decided at step #272that the first zone is the main zone, the program goes to step #273. Ifneither the zero zone nor the first zone is the main zone, that is, ifit is decided that the second zone is the main zone, the program goes tostep #274.

If it is decided that the first zone or the second zone is the mainzone, it is detected at steps #273 or #274 whether or not the zero zoneis an adjacent zone (refer to "in-focus detection routine", step #142 inFIG. 10). If it is decided that the zero zone is the adjacent zone, theprogram goes to steps #277 or #278. If it is decided that the zero zoneis not the adjacent zone, the program goes to steps #276 or #279.

As previously described, only when the photographing magnification β hasthe following relationship with respect to the predeterminedmagnifications β₁ (1/60 in this embodiment) and β₂, namely, β₁ <β≦β₂(for example, full-length figure in a lengthwise direction photographywhere the picture having a vertical dimension greater than a horizontaldimension is taken) and the focal length (f) of the photographing lensis longer than a predetermined value f₁ (28 mm in this embodiment), theprocessing of the "Bvs calculation II" is performed. Thus, since thephotographing magnification β is smaller than that at the time when theprocessing of the "Bvs calculation I" is performed, a light valuemeasured in a region smaller than the case of the "Bvs calculation I" isused. Similarly to the "Bvs calculation I", a weighted mean iscalculated by increasing the weight of a value measured in the vicinityof the main zone in which the main object is present. Thus, theluminance (Bvs) of the main object is calculated.

Specifically describing, as shown in Table 8, when the main object islocated in the center (zero zone) of the photographing image plane FLM,i.e., when the zero zone is the main zone, the luminance Bvs of the mainobject is calculated by the weighted mean at step #275 with the weightof the measured light value Bv0 in the region 1 in the region to bemeasured shown in FIG. 2 being 2 and with the weight of the measuredlight values Bv1 and Bv2 in the regions 2 and 3 in the region to bemeasured shown in FIG. 2 being 1. That is, ##EQU4##

In the case in which the main object is located to the left (first zone)to a slight amount with respect to the center of the photographing imageplane FLM, i.e., in case that the first zone is the main zone, when thezero zone is the adjacent zone, the luminance Bvs of the main object iscalculated at step #277 by the weighted mean with the weights of themeasured values Bv0 and Bv1 in the region 1 and 2 being 2 and with theweight of the measured value Bv2 in the region 3 being 1. That is,##EQU5##

If the zero zone is not the adjacent zone, the luminance Bvs of the mainobject is calculated at step #276 by the weighted mean with the weightof the measured value Bv1 in the region 2 being 2 and with the weight ofthe measured value Bv0 in the region 1 being 1. That is, ##EQU6## Inthis case, the measured light value Bv2 in the region 3 is not used whenthe luminance Bvs of the main object is calculated. This is because whenthe main object is located in the first zone, and if the zero zone isnot the adjacent zone, i.e., if an object located in the zero zone isnot an object (the same object as the main object) adjacent to the mainobject, the same object as the main object cannot be present in thesecond zone opposite to the first zone with the zero zone locatedtherebetween. Even though an object located in the second zone is notthe same object as the main object located in the first zone, theluminance of the object located in the second zone provides muchinfluence on the measured light value Bv2 if the object located in thesecond zone is adjacent to the main object to some extent. Therefore,the measured light value Bv2 is not used to calculate the luminance Bvaof the background.

On the other hand, if the main object is located to the right (secondzone) to a slight degree relative to the center of the photographingimage plane, i.e., if the second zone is the main zone, the luminance ofthe main object is calculated similarly to the case in which the firstzone is the main zone. If it is decided that the zero zone is theadjacent zone at step #274, the luminance of the main object Bvs iscalculated at step #278 by the following equation. ##EQU7## If it isdecided at step #274 that the zero zone is not the adjacent zone, theluminance Bvs of the main object is calculated at step #279 by thefollowing equation: ##EQU8##

When the luminance Bvs of the main object is calculated, the programreturns to the subroutine "exposure calculation" (step #237 in FIG.13b).

FIGS. 16a and 16b are flowcharts showing a subroutine "Bvs calculationIII". In this routine, the luminance Bvs of the main object iscalculated by the weighted mean adding the weights shown in Table 9 tothree measured light data Bv0, Bv1, and Bv2.

In this routine, similarly to the subroutine "Bvs calculation I" and"Bvs calculation II", it is decided at steps #281 and #282 which of thezero zone through the second zone is the main zone. If it is decided atstep #281 that the zero zone is the main zone, the program goes to step#283. If it is decided at step #282 that the first zone is the mainzone, the program goes to step #286. If it is decided that neither thezero zone nor the first zone is the main zone, i.e., if the second zoneis the main zone, the program goes to step #288.

When the program goes to step #283 after deciding that the zero zone isthe main zone, it is detected whether or not the first zone is theadjacent zone. Thereafter, it is detected at steps #284 and #285 whetheror not the second zone is the adjacent zone. If it is decided thatneither the first zone nor the second zone is the adjacent zone, theprogram goes to step #290. If it is decided that the first zone is notthe adjacent zone and the second zone is the adjacent zone, the programgoes to step #291. If it is decided that both the first and second zonesare the adjacent zones, the program goes to step #292. If it is decidedthat the first zone is the adjacent zone and the second zone is not theadjacent zone, the program goes to step #293.

When the program goes to step #286 after deciding that the first zone isthe main zone, it is detected whether or not the zero zone is theadjacent zone. If it is decided at step #286 that the zero zone is theadjacent zone, the program goes to step #287 at which it is detectedwhether or not the second zone is the adjacent zone. If it is decidedthat the second zone is not the adjacent zone, the program goes to step#293. If it is decided that the second zone is the adjacent zone, theprogram goes to step #294. If it is decided at step #286 that the zerozone is not the adjacent zone, the program goes to step #295.

In the case that it is decided that the second zone is the main zone,similarly to the case in which the first zone is the main zone, theprogram goes to step #297 if both the zero zone and the first zone arethe adjacent zones. If it is decided that the zero zone is the adjacentzone and the first zone is not the adjacent zone, the program goes tostep #298. If it is decided that the zero zone is not the adjacent zone,the program goes to step #296.

As previously described, the processing of the "Bvs calculation III" isexecuted only when the relationship between the photographingmagnification β and a predetermined magnifications β₀ (1/100 in theembodiment) and β₁ is β₀ <β≦β₁ (for example, full-size figure in awidthwise direction photography where a picture having a horizontaldimension greater than a vertical dimension is taken) and the focallength (f) of the photographing lens is longer than a predeterminedvalue f₀ (50 mm in the embodiment). Thus, the photographingmagnification β is smaller than that in the case of the processing of"Bvs calculation II". Accordingly, an arithmetic mean is performed byusing only a measured light value in a region to which the main zone orthe adjacent zone is related, whereby the luminance Bvs of the mainobject is calculated.

More specifically, as shown in Table 9, if there are no adjacent zones,the value of a region (zero, first, and second zones correspond to theregions 1, 2, and 3 (refer to FIG. 2)) to which the main zone is mostrelated is the luminance Bvs of the main object. And assuming that thezero zone is the main zone and the second zone is the adjacent zone, theluminance Bvs of the main object is calculated by the arithmetic mean ofthe measured light values Bv0 and Bv2 in the regions 1 and 3 to whichthe zero and second zone are related much. That is, ##EQU9## Similarlyto the "Bvs calculation II", if the first (second) zone is the main zoneand the zero zone is not the adjacent zone, the measured light value Bv2(Bv1) in the region to which the second (first) zone is related mostgreatly is not used when the luminance Bvs of the main object or theluminance Bva of the background is calculated.

When the luminance Bvs of the main object is calculated in this manner,the program returns to the subroutine "exposure calculation" (step #241in FIG. 3b) to perform the processing.

Calculation of exposure control value

FIG. 17 is a flowchart showing a subroutine of "slow synchronizedphotographing" (step #252 in FIG. 13b). In this subroutine, it isdetected at step #301 whether or not the voltage of the main capacitorMC provided in the flash circuit FLC is charged over a predeterminedvoltage (300 V). If the sixth bit FCR₀₅ of the data FCR₀ is reset, it isdecided that the voltage of the main capacitor MC is less than thepredetermined voltage, so that the program goes to step #302. If thevoltage of the main capacitor MC is charged over the predeterminedvalue, the program goes to step #305. When the program advances to step#302, "1" is stored in the indication data FLD₂ so as to indicate thatthe main capacitor MC is being charged. The sixth bit CFR₃₅ of the dataCFR₃ is set at step #303 to prohibit a flash emission, and the seventhbit CFR₃₆ of the data CFR₃ is reset at step #304 so that the indicatorCHD provided in the flash circuit FLC makes the indication. Then, theprogram goes to the spot light measuring routine (FIG. 21).

When the program goes to step #305 after deciding at step #301 that thevoltage charged with the main capacitor MC reaches the predeterminedvoltage, the luminance Bva of the background is used as the controlluminance value Bvc for calculating an exposure control value. This isbecause the slow synchronized photographing is effected by determiningthe exposure control value so that the background may be exposedcorrectly and by controlling the amount of the flash light so that themain objects may be exposed properly. Thereafter, the exposure controlmode is detected at steps #306 and #313. If the exposure mode is (S) or(M), the program goes to step #307. If it is (A), the program goes tostep #314. If it is (P), the program goes to step #316.

It is detected at step #307 whether or not a shutter speed Tvs set by aphotographer is faster than a flash synchronizing shutter speed Tvx (forexample, 1/100 sec.). If it is decided that the former is faster thanthe latter, the control shutter speed Tv is set at step #308 to theflash synchronizing shutter speed Tvx. If the latter is faster than theformer, the control shutter speed Tv is set at step #309 to the shutterspeed Tvs set by a photographer. And then, it is detected whether theexposure control mode is (S) or (M). If it is (M), the control aperturevalue Av is set at step #311 to an aperture value Avs set by aphotographer. If it is (S), an (S) mode calculation is performed at step#312 according to the following equation so as to calculate the controlaperture value Av:

    Av=Bvc+Sv-Tv.

If the exposure mode is (A), the control aperture value Av is set to anaperture value Avs set by a photographer at step #314, and an (A) modecalculation is performed at step #315 according to the followingequation so as to calculate the control shutter speed Tv:

    Tv=Bvc+Sv-Av.

If the exposure mode is (P), the control shutter speed Tv and thecontrol aperture value Av are calculated at step #316 based on thepredetermined program line. The control shutter speed Tv calculated asmentioned above is compared with the flash synchronizing shutter speedTvx at step #317. If the former is faster than the latter, the controlshutter speed Tv is set to the flash synchronizing shutter speed Tvx atstep #318 because a flash synchronization cannot be effected withshutter speed faster than the flash shutter speed Tvx, then the programgoes to step #312 so as to calculate the control aperture value again.

When the control shutter speed Tv and the control aperture value Av arecalculated, the program goes to the routine (FIG. 18) for executing an αcalculation.

In the embodiment, unless the main capacitor provided in the flashcircuit is charged to the predetermined voltage, the flash emission isprohibited and the flash emission mode is switched to a spot lightmeasuring photographing (refer to steps #301 through #304), but theflash emission may be always performed irrespective of the chargecondition of the main capacitor MC by omitting step #301 through #304,which is described later.

FIG. 18 is a flowchart showing the routine for executing the αcalculation. In this routine, first, at step #321, the microcomputer MCBcalculates the difference ΔEv between a control luminance value Bvc(namely, the luminance Bva of the background) and the luminance Bvs ofthe main object, namely, the exposure value to be compensated by theflash emission is calculated at step #321:

    ΔEv=Bvc-Bvs=Av+Tv-Sv-Bvs.

Thereafter, based on the ΔEv and the photographing magnification β, anexcessive exposure amount α (hereinafter referred to as emissioncompensation amount or merely compensation amount) when the flashemitting device emits a light to obtain correct exposure without ambientlight is calculated. First, it is detected at step #322 whether or notthe luminance difference ΔEv is greater than 1. If the luminancedifference ΔEv is greater than 1, that is, the exposure amount to becompensated by the flash emission is large, at step #323, thecompensation amount α is calculated depending on the luminancedifference ΔEv and the photographing magnification β. On the other hand,if the luminance difference ΔEv is less than 1, that is, the exposureamount to be compensated by the flash emission is small, at step #324,the compensation amount α is calculated depending on only thephotographing magnification β.

The luminance ΔEv is the difference between the luminance of the mainobject and that of the background. The microcomputer MCB calculates thecompensation amount α and reduces the emission amount so that the flashemitting device emits an amount corresponding to the difference ΔEv. Thereason for this is as follows:

The quantity of a light reflected from the main object changes accordingto the photographing magnification β, namely, the size of the mainobject with respect to the image plane. Therefore, unless the emissionamount is compensated, the main object cannot be exposed correctly. Forexample, if the photographing magnification β is small, the quantity oflight reflected from the main object is small. Accordingly, unless theemission amount is reduced, the exposure amount with respect to the mainobject exceeds the proper amount. In order to prevent this, thecompensation amount α with respect to the emission amount is calculatedaccording to the photographing magnification β and the luminancedifference ΔEv. Specifically, the smaller the photographingmagnification is, the greater the compesation amount α is so that theflash emitting device stops emitting light even though the amount of thelight reflected from the main object is small.

In the camera system of the embodiment, the compensation amount α undervarious conditions are calculated according to the actual photographingsand theoretical analysis, and the compensation amount α thus calculatedis stored in ROM of the microcomputer MCB, which is read as necessary.

It is detected at step #325 whether or not the flash stopping signalFSTP is outputted. If the fifth bit FCR₀₄ of the data FCR₀ is set, it isdecided that the flash stopping signal FSTP is outputted, and "10" isstored in the indication data FLD₂ at step #326 so that themicrocomputer MCB make the display circuit DSP display that flash lightis correctly emitted. If the fifth bit FCR₀₄ of the data FCR₀ is reset,it is decided that the flash stopping signal FSTP is not outputted, and"01" is stored in the indication data FLD₁ at step #327 so that thedisplay circuit DSP indicates that the main capacitor MC is completelycharged (when the program goes to this routine, the electric charge inthe main capacitor MC is completed.)

Thereafter, "01" is stored at step #328 so that the display circuit DSPmakes an indication that the camera system is under the flash emissionmode. Then, at step #329, the sixth bit CFR₃₅ of the data CFR₃ is resetto enable a flash emission and at step #330 the seventh bit CFR₃₆ of thedata CFR₃ is reset to allow the operation of the display circuit FDP andthe indicator CHD provided in the flash circuit FLC, then the programgoes to the data setting routine (FIG. 19).

FIG. 19 is a flowchart showing the routine for a data setting. In thisroutine, data to be transferred to the flash circuit FLC and the displaycircuit DSP are set, but the data (for example, FLD₁) set before theprogram goes to this routine are excluded.

First, the data CFR₀ through CFR₃ to be transferred from themicrocomputer MCB to the flash circuit FLC are set (refer to Table 5).The exposure control mode of the camera system and the film sensitivitySv are set in the data CFR₀ at step #331 and the focal length Fv of thephotographing lens is set in the data CFR₁ at step #332. The controlaperture value Avc is set in the data CFR₂ at step #333 and the emissioncompensation amount α is set in the data CFR₃ (low-order five bits) atstep #334.

Thereafter, the control shutter speed Tv is set in the indication dataTVD at step #336, the control aperture value Av is set in the indicationdata AVD at step #337, and the film sensitivity Sv is set in theindication data SVD. At step #329, the content of the AE lock flag ALFis set in the indication data ALD so that the display circuit DSPdisplays whether or not the AE lock is being effected.

When the data are set, the program returns to the "AE routine" (step #26in FIG. 5).

FIG. 20 is a flowchart showing the subroutine for executing "forcedemission". In this subroutine, similarly to "slow synchronizedphotographing", it is detected at step #341 whether or not the charge ofthe main capacitor MC of the flash circuit FLC is completed. If it isnot charged yet, "11" is stored at step #342 in the indication data FLD₂so that the display circuit DSP indicates that the main capacitor MC isbeing charged. Then, at step #343, the sixth bit CFR₃₅ of the data CFR₃is set to prohibit the flash emission, and at step #344, the seventh bitCFR₃₆ of the data CFR₃ is reset so that the indicator CHD provided inthe flash circuit FLC makes an indication (indication for showing thatthe main capacitor MC is being charged.) Thereafter, the processing ofthe available light routine (FIG. 22) is executed.

At step #341, if it is decided that charge of the main capacitor MC iscompleted, the processing steps subsequent to step #345 are executed.The luminance Bva of the background is selected at step 345 as thecontrol luminance value Bvc. Thereafter, the exposure control mode ofthe camera system is detected at steps #346 and #347. If the exposurecontrol mode is (M), the program goes to step #348, and if it is (A),the program goes to step #353, and if it is (S), the program goes tostep #356. As previously mentioned, there is no possibility that theprogram goes to this subroutine in (P) mode.

If the exposure control mode is (M), at step #348, shutter speed Tvs setby a photographer is compared with the synchronizing shutter speed Tvx.If the former is slower than the latter, i.e., if the flashsynchronizing is possible, the control shutter speed Tv is set to theshutter speed Tvs at step #351. If the former is not slower the latter,at step #352, the control shutter speed Tv is set to the synchronizingshutter speed Tvx. In both of the cases, the control aperture value Avis set to aperture value Avs set by a photographer at step #355.

If the exposure control mode is (A), the control shutter speed Tv is setto the synchronizing shutter speed Tvx at step #354, and the controlaperture value Av is set to aperture value Avs set by a photographer atstep #355.

If the exposure control mode is (S), the program goes to the subroutine"flash calculation" at step #356 so as to calculate the control shutterspeed Tv and the control aperture value Av.

After the exposure control values Tv and Av are set, the program goes tothe α calculation routine (FIG. 18) at which the above-describedprocessing of "data setting" is executed, then the program returns tothe AE routine (step #26 in FIG. 5).

In this embodiment, the flash emission is switched to available lightphotography (refer to steps #341 through 344) without using a flashemission if the main capacitor MC provided in the flash circuit FLC isnot yet charged to the predetermined voltage, but similarly to the slowsynchronized photographing (FIG. 17), the flash emission may be alwayseffected irrespective of the charge condition of the main capacitor byomitting the executions to be executed at step #341 through step #344.

FIG. 21 is a flowchart showing the subroutine for executing "flashcalculation".

In this subroutine, the aperture value Av is calculated at step #361assuming that the shutter speed is set to the synchronizing shutterspeed Tvx by the following equation. That is,

    Av=Bvc+Sv-Tvx.

Thereafter, at step #362, the aperture value Av calculated at step #361is compared with the maximum aperture value Avm (aperture valuecorresponding to the minimum aperture). If the former is greater thanthe latter, that is, if the aperture becomes smaller than the minimumaperture, the control aperture Av is set to the maximum aperture valueAvm at step #363. The maximum aperture value Avm is outputted from thelens circuit LEC to the microcomputer MCB.

When the aperture value Av calculated at step #361 is less than themaximum aperture value Avm, the aperture value Av is compared with theminimum aperture value Av0 (aperture value corresponding to openaperture) at step #364. The minimum aperture value Av0 is also outputtedfrom the lens circuit LEC to the microcomputer MCB. If the aperturevalue Av is greater than the minimum aperture value Av0, that is, theaperture value Av calculated at step #361 is within the controllablerange (Av0≦Av≦Avm), the aperture value Av is adopted as the controlaperture value Av.

If the aperture value Av calculated at step #361 is smaller than theminimum aperture value Av0 at step #364, the control aperture value Avis set to the minimum aperture value Av0 at step #365 so as to calculatethe shutter speed Tv at step #366 by the following equation:

    Tv=Bvs+Sv-Av0

The shutter speed calculated at step #366 is compared with thepredetermined shutter speed Tvh at step #367. The predetermined shutterspeed Tvh is the slowest shutter speed for preventing camera shake. Thelonger the focal length (f) is, the faster is the shutter speed Tvh (forexample, if f=50 mm, Tvh=6 (1/60 sec)). The shutter speed Tvh is storedin the ROM of the microcomputer MCB, which is read from the ROM asnecessary. At step #367, if the shutter speed Tv is slower than thepredetermined value Tvh, at step #368, the control shutter speed Tv isset to the shutter speed Tvh and the program returns. If the shutterspeed Tv is not slower than the predetermined value Tvh, the controlshutter speed Tv, is set to the shutter speed Tv calculated at step #366then the program returns.

If the aperture value calculated at step #361 is greater than themaximum aperture value Avm or in the controllable range, namely, Av≧Av0,the control shutter speed Tv is set to the flash synchronizing shutterspeed Tvx at step #369, then the program returns.

As described above, in the flash calculation routine, the aperture valueAv is calculated by assuming that the shutter speed Tv is thesynchronizing limit shutter speed Tvx, and if the value Av is smallerthan the minimum aperture value Av0, the aperture value Av is set to theminimum aperture value Av0, whereby the shutter speed Tv is calculated.If the shutter speed Tv calculated by setting the aperture value Av tothe minimum aperture value Av0 is the shutter speed at which the camerashake may occur (Tv<Tvh), the shutter speed Tv is set to the limitshutter speed Tvh which do not cause the camera shake. According to thisarrangement, when a flash is used (as described later, in the automaticemission mode, the processing of this routine is executed) except theslow synchronized photographing, the camera shake may not happen.

FIG. 22 is a flowchart showing the subroutine "available light" and"spot light measuring".

In the subroutine "available light", the control luminance value Bvc isset to the luminance Bvs of the main object at step #371. In thesubroutine "spot light measuring", the control luminance value Bvc isset to the measured value Bv0 in the region 1 located in the center ofthe photographing image plane. In both cases, the program goes to stepssubsequent to step #373.

The exposure control mode of the camera system is detected at step #373through #375.

If "00" is stored in the exposure control mode register MOR, it isdecided at step #373 that the exposure control mode is (P) and thecontrol aperture value Av and the control shutter speed Tv arecalculated at step #376 based on the predetermined program line.

If "01" is stored in the exposure control mode register MOR, it isdecided that the exposure control mode is (S) at step #374, so that (S)mode calculation is performed as follows so as to calculate the controlaperture value Av, and the control shutter speed Tv is set to theshutter speed Tvs set by a photographer at step #377:

    Av=Bvc+Sv-Tvs.

If "10" is stored in the exposure control mode register MOR, it isdecided at step #375 that the exposure control mode is (A), so that the(A) mode calculation is performed by the following equation so as tocalculate the control shutter speed Tv, and the control aperture valueAv is set to the aperture value Avs set by a photographer at step #378:

    Tv=Bvc+Sv-Avs.

If it is decided that the exposure control mode is not (P), (S), or (A),namely, the exposure control mode is (M), the control aperture value Avand the control shutter speed Tv are set to the aperture value Avs andthe shutter speed Tvs both set by a photographer, respectively at step#379.

As previously described, in this embodiment, in the routine of the "slowsynchronized photographing" or the "forced emission" in which the flashemission is used, if the main capacitor MC provided in the flash circuitFLC is not charged to the predetermined voltage, the processing of theseroutines are suspended and instead the processing of the "spot lightmeasuring" or "available light" which do not require the flash emissionis executed. Therefore, when the control aperture value AV and thecontrol shutter speed Tv are set, it is detected at step #380 whether ornot the program progresses from the subroutine "slow synchronizedphotographing" to the subroutine "spot light measuring" or from thesubroutine "forced emission" to the routine "available light". When theprogram progresses from the subroutine "slow synchronized photographing"or the subroutine "forced emission" to these routines, "11" is alwaysstored in the indication data FLD₂ (refer to step #302 in FIG. 17 andstep #342 in FIG. 20). Accordingly, the above-described progresses ofthe program from the subroutine "slow synchronized photographing" or"forced emission" to the subroutine "spot light measuring" or "availablelight" are detected according to the data stored in the indication dataFLD₂. If the program goes from the subroutine "slow synchronizedphotographing" of the "forced emission" to this routine, the programskips to step #382. If not, that is, if the exposure control modewithout using the flash emission is set by the photographer and theprogram goes from steps #254 and #257 to step #266 or from step #228 tostep #259 in the subroutine "exposure calculation" (FIGS. 13a, 13b),"00" is stored in the indication data FLD₂ at step #381 so that thedisplay circuit DSP clears the indication of the flash information, thenthe program goes to step #382.

At step #382, it is detected whether or not the flash stopping signal isoutputted from the flash circuit FLC. If the fifth bit FCR₀₄ of the dataFCR₀ is set, it is decided that the flash stopping signal is outputted,and "10" is stored at step #383 in the indication data FLD₁ so that thedisplay circuit DSP makes the indication to that effect. If the flashstopping signal is not outputted, "00" is stored in the indication dataFLD₁ at step #384 so that the display circuit DSP clears the indicationof the flash information. Thereafter, at step #385, the sixth bit CFR₃₅of the data CFR₃ is set to set the flash emitting device to thenon-emission mode, and at step #386 the seventh bit CFR₃₆ of the dataCFR₃ is reset to enable the operations of the display circuit FDP andthe indicator CHD of the flash circuit FLC. Thereafter, the program goesto the "data setting" routine (FIG. 19) previously described and returnsto the AE routine (step #26 in FIG. 5).

FIGS. 23a, 23b, 23c and 23d are flowcharts showing the subroutine"automatic emission". This subroutine is divided into four parts. Thefirst part is to decide the exposure amount depending on natural light(step #401 through #410, #429 and #430). The second part is to calculatethe flash emission amount to be compensated to expose the main objectcorrectly (step #411 through #415). The third part is decided whether ornot a flash light is required (step #416 through #425). The last part isto set data (step #426 through #428, step #431 through #440 and a datasetting routine (FIG. 19)).

The respective photographing conditions of this subroutine is describedhereinbelow. The photographing conditions include a high luminance frontlight (light is emitted from back of photographer, hereinafter referredto merely front light), a high luminance rear light (hereinafterreferred to as merely rear light), a low luminance front light, and alow luminance rear light. The light condition in the respectivephotographing conditions are as shown in FIG. 35. That is,

    ______________________________________                                        front light      Bvs ≧ Bvh and Bva < Bvs + 2                           rear light       Bvs ≧ Bvh and Bva ≧ Bvs + 2                    low luminance front light                                                                      Bvs < Bvh and Bva < Bvh + 1                                  low luminance rear light                                                                       Bvs < Bvh and Bva ≧ Bvh + 1                           ______________________________________                                    

First, the photographing to be made under a front light is described. Inthis case, the exposure control values Av and Tv are determined based onthe luminance Bvs of the main object, and the main object isphotographed without a flash emission.

First, the threshold luminance value Bvh which is the lowest valuepreventing camera shake is calculated at step #401. The luminance valueBvh is the luminance value that correct exposure is obtained when theshutter speed is set to the value Tvh which is the slowest shutter speedfor preventing camera shake and the aperture value is set to the minimumaperture value Avo:

    Bvh=Tvh+Av0-Sv.

When the minimum aperture value Av0 is smaller than 3 Ev (F2.8), theaperture value Av0 is not used, but the following equation may be used:

    Bvh=Tvh+3-Sv.

Thereafter, it is detected at step #402 whether or not the luminance Bvsof the main object is in the range in which the camera shake may occur.Under the front light condition, as apparent from FIG. 35, the luminanceBvs of the main object is not in that range. Accordingly, the programgoes to step #402 so as to reset the low luminance flag LLF. Thereafter,the difference between the luminance Bvs of the main object and theluminance Bva of the background ΔBv=Bva-Bvs is calculated at step #404and it is detected at step #405 whether or not a photograph is takenunder a rear light at step #405. Under the front light, the program goesfrom step #405 to #426, then "10" is stored in the indication data FLD₂so that the display circuit DSP displays that the mode is thenon-emission mode. Then, the control luminance value Bvc is set to theluminance Bvs of the main object at step #429, and the control aperturevalue Av and the control shutter speed Tv are calculated at step # 430in accordance with the predetermined program. Thereafter, it is detectedat step #431 whether or not the flash stopping signal FSTP is outputtedfrom the flash circuit FLC. If the flash stopping signal FSTP isoutputted, "10" is stored in the indication data FLD₁ at step #432 sothat the display circuit DSP indicates that flash light is correctlyemitted. If the flash stopping signal is not outputted, "00" is storedin the indication data FLD₁ at step #433 so as to clear the indicationthat the flash light is correctly emitted. At step #434, the sixth bitCFR₃₅ of the data CFR₃ is set to prohibit a flash emission, and at step#435, the seventh bit CFR₃₆ of the data CFR₃ is reset to allow theoperations of the display circuit FDP and the indicator CHD provided inthe flash circuit FLC. Then, the program goes to the data settingroutine (FIG. 19), and then returns to the AE routine (step #26 in FIG.5).

Next, a photographing under the rear light is described. In the case ofthe rear light, the main object is exposed correctly, and the backgroundis over-exposed by 1 Ev than the main object, whereby the exposurecontrol value is determined so that the contrast under the rear light iskept and the effect of the rear light appears on a picture.

Similarly to the front light, when the program goes from #401 to #405,the rear light is detected. Then, the program goes to step #406. Then,the control luminance value Bvc is set to the value which is less thanthe luminance Bva of the background by 1 Ev. Since the control aperturevalue Av and the control shutter speed Tv are calculated by the controlluminance value Bvc, the background is over-exposed by 1 Ev.

Similarly to the "α calculation routine" (FIG. 18), the difference ΔEvbetween the control luminance value Bvc and the luminance value Bvs ofthe main object is calculated at step #411, wherein the difference ΔEvis light amount to be supplemented by the flash emission so that themain object may be exposed correctly. And then, the compensation amountα is calculated depending on the photographing magnification β and thedifference ΔEv. As described above, in consideration of the light whichis reflected from the main object and which changes according to thephotographing magnification β (the ratio which the main object forms inthe photographing image plane FLM), the compensation amount α iscalculated so that the flash light may emit by the shortage amount oflight with only natural light. The compensation amount α can be found bydetermining the relationship between the compensation amount α and thephotographing magnification β as well as the shortage light amount ΔEvbased on data obtained by photographs taken in various conditions. Thecompensation amount α can be formulated according to the above-describedphotographing magnification β and the shortage light quantity ΔEvexperimentally obtained. Or a ROM which stores data of the compensationamount α based on the photographing magnification β and the shortagelight amount ΔEv may be prepared.

After the compensation amount α is found, at step #416, the aperturevalue Avd is calculated by performing the FM operation according to thefollowing equation in consideration of the compensation amount α:

    Avd=Iv-α+Sv-Dv,

wherein the aperture value Avd is the maximum aperture value with whichflash light is correctly emitted. In the above equation, Iv is themaximum emission amount of the flash emitting device and Dv is aphotographing distance. At step #417, it is detected whether or not themain object will be correctly exposed with the compensation light amountα. If the aperture value Avd calculated at step #416 is smaller than theminimum aperture value Av0, a proper amount of flash light does notreach the main object and even if the aperture size is increased to thegreatest extent, an emission amount is short, which causes the mainobject to be exposed inappropriately. If the aperture value Avd isgreater than the minimum aperture value Av0, the main object will beexposed properly with the aperture value Av of Av0≦Av≧Avd.

If it is decided at step #417 that the main object will not beappropriately exposed, the program goes to step #418 at which it isdetected whether or not camera shake will happen. That is, if the lowluminance flag LLF is set, it is decided that camera shake may happen,the program goes to step #419, and if the flag LLF is reset, the programgoes to step #426. Assuming that a photograph is taken under the rearlight, the flag LLF is reset. Accordingly, if the main object is notexposed appropriately, the program goes from step #418 to step #426, andthe microcomputer MCB executes the processing as in the case of thefront light.

If it is decided at step #417 that it is possible to expose the mainobject correctly, the program goes to step #421. At this step #421, theluminance value Bvx is calculated according to the following equation:

    Bvx=Tvx+Avd-Sv,

the luminance value Bvx is the luminance value of an object which iscorrectly exposed with the synchronizing shutter speed Tvx and theaperture value Avd calculated at step #416. Then, the control luminancevalue Bvc is compared with the luminance value Bvx at step #422. IfBvx≧Bvc at step #422, the program goes to the subroutine "flashcalculation" in which the control shutter speed Tv and the controlaperture value Av are determined according to the control luminancevalue Bvc at step #423. At this time, as previously described, thefollowing equation is satisfied:

    Bvc=Av+Tvx-Sv.

While, according to step #421, the following equation is satisfied:

    Bvx=Avd+Tvx-Sv.

Accordingly, the following equation is satisfied:

    Bvc-Bvx=Av-Avd.

Consequently, if Bvx<Bvc, Av>Avd so that the control aperture value Avbecomes greater than the maximum aperture value Avd with which flashlight is correctly emitted, therefore, the emission amount is short andthe main object is not exposed properly. Conversely, if Bvx≧Bv, Av≧Avd.This control aperture value Av does not cause the emission amount to beshort. As described above, at step #422, the luminance values Bvc iscompared with the luminance value Bvx to detect whether or not the mainobject is exposed properly. If Bvx<Bvc, the program goes to step #424 atwhich the control luminance value Bvc is set to the luminance value Bvx,and then, the processing is resumed from step #411. Owing to the controlaperture value Av and the luminance value Bvx, while the background isover-exposed, the main object is exposed properly.

If it is decided at step #422 that Bvx≧Bvc, the program goes to thesubroutine "flash calculation" (step #423 in FIG. 22) at which thecontrol shutter speed Tv and the control aperture value Av aredetermined, then the program goes to step #425. It is detected at step#425 whether or not the main capacitor MC in the flash circuit FLC ischarged to the predetermined voltage. If the sixth bit FCR₀₅ of the dataFCR₀ is set, it is decided that the main capacitor MC is charged in thepredetermined voltage, so that the program goes to step #428. If not,the program goes to step #427.

At step #427, "11" is stored in the indication data FLD₂ so that thedisplay circuit DSP indicates that the main capacitor MC is beingcharged, then the same as in the case of the front light, processing iscontinued from step #429. Accordingly, in this case, a control shutterspeed Tv and a control aperture value Av are newly determined by theluminance Bvs of the main object.

At step #428, "00" is stored in the indication data FLD₂ so that thedisplay circuit DSP indicates that the camera system is in the emissionmode. Then, the program goes to step #436. At step #436, it is detectedwhether or not the flash stopping signal FSTP is outputted from theflash circuit FLC. If it is decided that the flash stopping signal FSTPis outputted, "10" is stored in the indication data FLD₁ at step #437 sothat the display circuit DSP indicates that the flash light is correctlyemitted, while if it is decided that the flash stopping signal FSTP isnot outputted, "01" is stored in the indication data FLD₁ at step #438so that the display circuit DSP indicates that the charging operation ofthe main capacitor MC is completed. Thereafter, the sixth bit CFR₃₅ ofthe data CFR₃ is reset at step #439 to allow the flash emission, and theseventh bit CFR₃ of the data CFR₃ is reset at step #440 to allow theoperation of the display circuit FDP and the indicator CHD. Then, theprogram goes to the data setting routine (FIG. 19). Thereafter, theprogram returns to AE routine (step #26 in FIG. 5).

Next, photographings performed in a low luminance front light or in alow luminance rear light are described. Under these conditions, thephotographing operation is carried out with the shutter speed set to aspeed higher than the value Tvh with which camera shake may occur andwith flash emission in order to compensate a shortage light amount dueto this shutter speed.

In these cases, when the program goes from step #401 to step #402,different from a photograph effected in a high luminance, it is decidedat step #402 that the luminance Bvs of the main object is located in theregion in which the camera shake may occur, and the program goes to step#407 at which the low luminance flag LLF is set. Based on the luminanceBva of the background, it is detected whether the photographingcondition, namely, the light condition of the image plane, is in a lowluminance front light or a low luminance rear light at step #408. Thatis, it is detected whether the photographing is being carried out in theregion III or IV in FIG. 35. If it is decided that the photographingcondition is the low luminance front light (region IV in FIG. 35), theprogram goes to step #410 at which the control luminance value Bvc isset to 1 Ev greater than the luminance Bvh which is the lower limit ofluminance that camera shake may not occur:

    Bvc=Bvh+1.

With this arrangement, the main object is inappropriately exposed underonly available light, and owing to the control luminance value Bvc, thecontrol shutter speed Tv is always set to a shutter speed higher thanthe slowest shutter speed Tvh for preventing camera shake. Therefore aphotographed image is not blurred.

On the other hand, if it is decided that the main object is photographedin a low luminance rear light (region III in FIG. 35), the program goesto step #409, and similarly to the rear light, the control luminancevalue Bvc is set so that the main object is correctly exposed and thebackground is over-exposed by 1 Ev. That is,

    Bvc=Bva-1.

Thereafter, similarly to the case of the rear light, the program goesfrom step #411 to #417 in the both cases. If it is detected at step #417that Avd≧Av0, processing identical to the case of the rear light isexecuted. If it is decided at step #417 that Avd<Av0, that is, if it isdecided that the flash light does not reach the main object in asufficient amount so that the main object is not exposed sufficiently,the program goes from step #418 to step #419 because the low luminanceflag LLF is set unlike the rear light. At step #419, the control shutterspeed Tv is set to the limit value Tvh, and then, the control aperturevalue Av is set to the minimum aperture value Av0 at step #420, wherebythe degree to which the exposure amount becomes short can be minimized.Then, the program goes to step #425, and the same processing as the caseof the rear light is executed.

Exposure control

FIG. 24 is a flowchart showing the subroutine "exposure control". Whenthe release button is depressed to the second stroke so as to turn onthe release switch S₂, the program goes from step #32 to #33 of the AEroutine, that is, the program goes to step #451 in FIG. 24 to executethe processing.

First, data for repelling the release magnets RLM is transferred to thedrive circuit DDR so as to move away the mirror provided diagonally inthe photographing optical path from the optical path and release theaperture. Thus, the aperture begins to be stopped down at step #451.Thereafter, it is detected at step #452 whether or not the controlaperture value Av equals to the minimum aperture value Av0. If thecontrol aperture value Av is equal to the minimum aperture value Av0,data for repelling the magnet APM is transferred to the drive circuitDDR so as to stop the stopping down operation at step #453, then theprogram goes to step #457. If the control aperture value Av is unequalto the minimum aperture value Av0, the difference between the controlaperture value Av and the minimum aperture value Av, namely, theinformation of the aperture step difference Av-Av0 is set in the eventcounter at step #454, and "H" is outputted from the terminal P₁₅ so thatthe pulse outputted from the encoder ENAP is inputted to the counterterminal CNT at step #455. Thereafter, the counter interruption CNT isallowed at step #456. Then, the program goes to step #457. When thestopping down operation is completed, the event counter causes thecounter interruption CNT. As previously described about the counterinterruption routine CNT (FIG. 10), data for repelling the magnets APMis transmitted to the drive circuit DDR. Thus, the aperture stoppingdown operation is completed.

At step #457, the microcomputer MCB waits until the mirror completelymoves away from the photographing optical path. The waiting period isset to be longer than the period required for the aperture size to bereduced to the minimum.

Thereafter, at step #458, the corrected reference value Sv+α forstopping flash emission is outputted to the light measuring interfaceLIF. Consequently, the D-A converter mounted in the interface LIFconverts the reference value Sv+α into an FSL signal which is ananalogue amount. Thereafter, the FSL signal is outputted to the flashlight measuring circuit LMF.

As described previously, the flash light measuring circuit LMF comprisesthe light receiving element PDF. The light receiving element PDFreceives a light which has been reflected from the main object, passedthrough the photographing lens, the aperture, and reflected from thefilm. The flash light measuring circuit LMF performs a logarithmiccompression of the electric current emitted from the light receivingelement PDF, thus converting the electric current into a voltage.Thereafter, the flash light measuring circuit LMF adds the informationSv of the film sensitivity and the emission amount compensation amount αto each other, namely, Sv+α, then adds the voltage corresponding to Sv+αto the voltage obtained by the logarithmic compression, and then,performs the logarithmic expansion of the voltage obtained by theaddition, thereby converting the added voltage into electric current. Onthe other hand, when an contact Sx is turned on, the flash controlcircuit FCC outputs an emission start signal STA to the emission controlcircuit XCC and an integration start signal ISTA to the flash lightmeasuring circuit LMF through the terminal J₇. In response to the signalISTA, the flash light measuring circuit LMF starts integrating thelogarithmically expanded electric current. Thereafter, when theintegrated value reaches the proper exposure amount, the flash lightmeasuring circuit LMF outputs the flash stopping signal FSTP to theflash control circuit FCC through the terminal P₆. In response to theflash stopping signal FSTP, the flash control circuit FCC outputs theemission stop signal STOP to the emission control circuit XCC to stopthe flash emission. Accordingly, the emission amount corresponding tothe compensation amount α is reduced, which appropriately exposes themain object using the flash light and the natural light. Theconstruction of the flash light measuring circuit LMF is disclosed, forexample, in Japanese Utility Model Laid-Open Publication No.121034/1986.

Next, at step #459, data for repelling the attracting portions of themagnets 1CM is transmitted from the microcomputer MCB to the drivecircuit DDR, whereby the first curtain of the shutter travels. When theexposure time counted by the microcomputer MCB at step #460 becomesequal to the control exposure time Tv (already set), data for repellingthe attraction portions of the magnets 2CM is transmitted to the drivecircuit DDR. As a result, the second curtain of the shutter travels atstep #461. Thereafter, at step #462, "L" is outputted from the terminalP₁₅ so that the pulse generated by the encoder ENLE can be inputted tothe counter terminal CNT.

Thereafter, the microcomputer MCB waits at step #463 until thephotograph completion detecting switch S₄ is turned on. As describedabove, the switch S₄ is turned on when the mirror pivots downward, theaperture is fully opened, and the travelling of the second curtain ofthe shutter is completed. When the switch S₄ is turned on, "1" is addedto the indication data CND at step #464 and the indication data istransferred to the display circuit DSP so that at step #465 the displaycircuit DSP indicates the number of exposed frames of the film, exposureinformation, and so on. Then, at step #467, data for driving the filmfeeding motor MOFI is transmitted to the motor control circuit MODthrough the drive circuit DDR to wind up the film, whereby the chargemechanism interlocked with the film-winding mechanism is actuated. As aresult, the shutter, the mirror, and the diaphragming mechanism arecocked. At step #468, the microcomputer MCB waits until the photographcompletion detecting switch S₄ is turned off. As described previously,when the film-winding mechanism, the shutter, the mirror, and thediaphragming mechanism have been cocked, the switch S₄ is turned off.When the switch S₄ is turned off, at step #469, the data for stoppingthe film feeding motor MOFI is transmitted to the motor control circuitMOD through the drive circuit DDR. Thereafter, the program goes to theswitch determining routine II (FIG. 7).

If the microcomputer detects that the film is excessively tensed whilethe film is being wound, the film is rewound by a known method althoughthe step for performing this operation is not shown in any of theflowcharts.

The above is the description of the operation of the embodiment to beperformed when the light measuring switch S₁ or the AE lock switch ALSare turned on. (System reset)

FIG. 25 is a flowchart showing the subroutine for "system reset". Inthis subroutine, the exposure control mode of the camera system is setto (P), and the flash emitting device is set to the automatic emissionmode, the automatic flash stopping mode, and the illumination angleautomatic change-over mode.

As described previously, when the reset switch SRS is turned on, thevoltage level of the interruption terminal INT₀ falls and themicrocomputer MCB operates according to the flowchart shown in FIG. 4.The program goes to the subroutine "system reset" (step #14) throughsteps #1, #2, #3, #10, and #13 and executes processing from step #601shown in FIG. 25.

First, "00" is stored in the mode register MOR, i.e., the exposurecontrol mode is set to (P) mode at step #601, and the content of theregister MOR, namely, "00" is stored in the indication data MOD so thatthe display circuit DSP indicates the exposure control mode, namely, (P)mode. Then, the blank indication data BLD is stored in the indicationdata TVD and AVD at step #603 and #604, "00" is stored in the indicationdata FLD₁ and FLD₂ at steps #605 and #605, "00" is stored in theindication data AFD at step #607, and "0" is stored in the indicationdata ALD at step #608 so that the display circuit DSP clears theindications of the control exposure value, the flash data, the in-focusstate, and the AE lock state. Then, at step #609, "00" is stored in thehigh-order two bits CFR₀₇ and CFR₀₆ of the data CFR₀ so as to inform theflash emitting device that the exposure control mode is (p). Further, atstep #610, the most significant bit CFR₃₇ of the data CFR₃ is set sothat the system reset of the flash emitting device is effected, and theseventh bit CFR₃₆ of the data CFR₃ is set so as to stop the operationsof the display circuit FDP and the indicator CHD provided in the flashcircuit FLC.

When the above-described data have been set, the indication data istransmitted to the display circuit DSP through the data bus SDB, at step#611, and the flash data CFR₀ through CFR₃ are transmitted to the flashcircuit FLC through the data bus SDB at step #612.

Thereafter, the microcomputer MCB waits until the reset switch SRSbecomes OFF at step #613. If the "H" is inputted to the terminal P₈, itis decided that the reset switch SRS is OFF, so that the program goes tostep #614. Accordingly, if the reset switch is kept depressed, thesystem reset is effected only once. When the program goes to step #614after the reset switch becomes OFF, the most significant bit CFR₃₇ ofthe data CFR₃ is reset to inform the microcomputer MCF of the flashcircuit FLC that the camera system has been reset. Thereafter, theprogram returns and goes to the above-described STOP routine (FIG. 8),and the microcomputer MCB waits until the interruption INT₀ occursagain.

Change of exposure control mode

FIGS. 26a and 26b are flowcharts showing the subroutine "mode change".In this subroutine, the exposure control mode of the camera system ischanged. As described above, every time the mode change-over switch MOSis turned on, the exposure control mode changes in the order of P, S, A,M, and to P.

As previously described, when the mode change-over switch MOS is turnedon, the voltage level of the interruption terminal INT₀ falls, and theprogram goes to the subroutine "mode change" (step #16) through step #1,#2, #3, #10, #13, and #15, then the processing is executed from step#701 shown in FIG. 26.

First, the content of the mode register MOR is checked at step #701. Ifthe content of the register MOR is "11", "00" is stored in the registerMOR at step #702. If the content of the register MOR is not "11", theregister MOR is incremented, that is, "1" is added to the content of theregister MOR. After the mode register MOR is set, the content of theregister MOR is transferred to the indication data MOD at step #704 sothat the display circuit DSP changes the indication of the exposurecontrol mode.

Thereafter, so that the display circuit DSP clears the indications ofthe flash data, the in-focus state, and the AE lock state, "00" isstored at step #705 in the indication data FLD₁ and FLD₂, "00" is storedin the indication data AFD at step #706, and "0" is stored in theindication data ALD at step #707.

Thereafter, it is detected at step #708 through #710 to which of theexposure control modes the camera system is switched. If the exposurecontrol mode is switched to (M) mode, the shutter speed Tvs previouslyset is stored in the indication data TVD at step #711 and the aperturevalue Avs previously set is stored in the indication data AVD at step#712 so that the display circuit DSP makes an indication of the shutterspeed Tvs and the aperture value Avs both set previously. When theexposure control mode is switched to (S) mode, the shutter speed Tvspreviously set is stored in the indication data TVD at step #713 and theblank indication data BLD is stored in the indication data AVD at step#714 so that the display circuit DSP indicates only the shutter speedTvs set previously. When the exposure control mode is switched to (A)mode, the blank indication data TVD is stored in the indication data TVDat step #715 and the aperture value Avs previously set is stored in theindication data AVD at step #716 so that the display circuit DSPindicates only the aperture value Avs previously set. When the exposurecontrol mode is switched to (P) mode, the blank indication data BLD isstored at steps #717 and #718 in the indication data TVD and AVD so thatthe display circuit DSP is prohibited to indicate the shutter speed Tvand the aperture value Av.

When the indication data TVD and AVD are set, the content of the moderegister MOR is transferred to the high-order two bits CFR₀₇ and CFR₀₆of the data CFR₀ at step #719 so as to inform the flash circuit FLC ofthe exposure mode. Thereafter, at step #720, the seventh bit CFR₃₆ ofthe data CFR₃ is set to prohibit the operations of the display circuitFDP and the indicator CHD provided in the flash circuit FLC.

When the indication data and the flash data are set, through the databus SDB, the indication data are transferred to the display circuit DSPat step #721, and the flash data is transferred to the flash circuit FLCat step #722.

Thereafter, the microcomputer MCB waits at step #723 until the modechange-over switch becomes OFF. Accordingly, even if the exposurecontrol mode change-over switch MOS is kept ON, the exposure controlmode is not switched again. When the switch MOS is turned OFF, theprogram returns from this subroutine and progresses to the STOP routine(FIG. 8), and the microcomputer MCB waits until the interruption INT₀occurs again.

Data setting

FIGS. 27a and 27b are flowcharts showing the subroutine "data change".

As previously described, when either the data setting switch US or DS isturned on, the voltage level of the interruption terminal INT₀ falls andthe microcomputer MCB operates in accordance with the flowchart shown inFIG. 4. After going through steps #1, #2, #3, #13, and #15, the programgoes to the subroutine "data change" (#17), i.e., the processing isexecuted from step #801 of the flowchart shown in FIGS. 27a and 27b.

First, the exposure control mode is detected at step #801 through step#803. If the exposure control mode is (M), the program goes to step #804at which it is detected which of the shutter speed Tvs and the aperturevalue Avs is going to be changed. When the change-over switch ASS is ON,that is, and "L" is inputted to the terminal P₁₄, it is decided that theaperture value Avs is going to be changed, then the program goes to tostep #805 so as to change the aperture value Avs. On the other hand,when the change-over switch ASS is OFF, that is, and "H" is inputted tothe terminal P₁₄, it is decided that the shutter speed Tvs is going tobe changed, so that the program goes to step #806 to change the shutterspeed Tvs.

If the exposure control mode is (A), the aperture value is changed atstep #807 regardless of whether the change-over switch ASS is ON or OFF.If the exposure control mode is (S), the shutter speed Tvs is changed atstep #808 regardless of whether the switch ASS is ON or OFF.

When the shutter speed Tvs or the aperture value Avs has been changed,at steps #809 through #816, the data which indicates the changed shutterspeed Tvs or aperture value Avs is stored in the indication data TVD orAVD, and the blank indication data BLD is stored in the indication dataAVD or TVD so that the display circuit DSP indicates only the changedshutter speed Tvs or aperture value Avs.

When the exposure control mode is (P), the data is not changed in thissubroutine because neither the shutter speed Tvs nor the aperture valueAvs is set, and the blank indication data BLD is stored in theindication data TVD and AVD at steps #817 and #818 so that the displaycircuit DSP is prohibited to indicate neither the shutter speed Tvs northe aperture value Avs.

When the shutter speed Tvs and the aperture value Avs have been changedand the indication data TVD and AVD have been set, "00" is stored in theindication data AFD at step #819, "0" is stored in the indication dataALD at step #820, "00" is stored in the indication data FLD₁ at step#821, and "00" is stored in the indication data FLD₂ at step #822 sothat the display circuit DSP clears the indication of the in-focusstate, the indication of the AE lock, and the indication of the flashinformation. Thereafter, at step #823, the seventh bit CFR₃₆ of the dataCFR₃ is set at step #823 to stop the operation of the display circuitFDP and the indicator CHD of the flash circuit FLC. Then, the indicationdata are transmitted from the microcomputer MCB to the display circuitDSP through the data bus SDB at step #824, and the flash data aretransmitted to the flash circuit FLC through the data bus SDB at step#825.

When the data have been outputted, the microcomputer MCB waits until thesetting switches US and DS are both OFF at steps #826 and #827, and thenthe program returns from this subroutine. Thereafter, the program goesto the STOP routine (FIG. 8), and the microcomputer MCB waits until theinterruption INT₀ occurs again.

FIG. 28 is a flowchart showing the subroutine "Tv change" shown in thesubroutine "data change" (FIGS. 27a and 27b). In this subroutine, theshutter speed Tvs is increased by 1 Ev when the setting switch US is ON,and the shutter speed Tvs is reduced by 1 Ev when the setting switch DSis ON.

First, it is detected whether or not the setting switch US is ON at step#831. If the "L" is inputted to the terminal P₁₀, it is decided that theswitch US is ON, then the program goes to step #832. If not, it isdecided that the setting switch DS is ON, then the program goes to step#833.

When the program goes to step #832 with the setting switch US being ON,the shutter speed Tvs is increased by 1 Ev. If the changed shutter speedTvs is faster than the fastest shutter speed Tvm (for example, 1/4000sec.) of the camera at step #834, the shutter speed Tvs is again set tothe fastest shutter speed Tvm at step #836.

When the program goes to step #833 with the setting switch DS being ON,the shutter speed Tvs is reduced by 1 Ev. If the changed shutter speedTvs is slower than the slowest shutter speed Tv0 (for example, 30 sec.)of the camera at step #385, the shutter speed Tvs is again set to theslowest shutter speed Tv0 at step #837.

When the shutter speed Tvs has been changed, the program returns to thesubroutine "data change" (FIGS. 27a and 27b) to continue executing theprocessing.

FIG. 29 is a flowchart showing the subroutine "Av change" shown in thesubroutine "data change" (FIGS. 27a and 27b). In this subroutine, whenthe setting switch US is ON, the aperture value Avs is increased by 1/2Ev, and when the setting switch DS is ON, the aperture value Avs isreduced by 1/2 Ev.

First, it is detected at step #841 whether or not the setting switch USis ON. If "L" is inputted to the terminal P₁₀, it is decided that theswitch US is ON, then the program goes to step #842. If "L" is notinputted to the terminal P₁₀, it is decided that the setting switch DSis ON, then the program goes to step #843.

When the program goes to step #842 with the setting switch being ON, theaperture value Avs is increased by 1/2 Ev. If the changed aperture valueAvs is greater than the maximum aperture value Avm (inputted from thelens circuit LEC) of the photographing lens at step #844, the aperturevalue Avs is set to the maximum aperture value Avm at step #846.

If the program goes to step #843 with the setting switch being ON, theaperture value Avs is reduced by 1/2 Ev. If the changed aperture valueAvs is smaller than the minimum aperture value Av0 at step #845, theaperture value Avs is again set to the minimum aperture value Av0 atstep #847.

When the aperture value Avs has been changed, the program returns to thesubroutine "data change" to continue the processing.

Microcomputer MCF

FIGS. 30 through 34 are flowcharts showing the operation of themicrocomputer MCF provided in the flash emitting device (FIG. 3) of thecamera system of the embodiment.

INTA

When either of the flash stopping mode change-over switch ATS, theillumination range change-over switch VCS, and the emission modechange-over switch MES is turned on, the level of the interruptionterminal INTA of the microcomputer MCF falls, and in synchronization ofthe fall, the microcomputer MCF starts its operation in accordance withthe flowchart shown in FIGS. 30a and 30b.

It is detected at steps #5001 and #5002 which of the switches causes theinterruption INTA. That is, if the terminal P₂₀ is "L" at step #5001, itis decided that the interruption INTA is caused by the operation of theflash stopping mode change-over switch ATS, so that the program goes tostep #5003. If the terminal P₂₀ is "H", the program goes to step #5002.If the terminal P₂₁ is "L" at step #5002, it is decided that theinterruption INTA is caused by the illumination range change-over switchVCS, then the program goes to step #5021. If the terminal P₂₁ is "H" atstep #5002, it is decided that the interruption is caused by theemission mode change-over switch MES, then the program goes to the MESroutine (FIG. 31).

Change-over of flash stopping mode

When the interruption INTA is caused by the flash stopping modechange-over switch ATS, the state of the flag STF is checked at step#5003. If the flag STF is set at step #5003, the program goes to step#5004. If the flag STF is reset at step #5003, the program skips to step#5005. At step #5004, the exposure control mode of the camera system isdetected. If the exposure control mode is (M), the program goes to step#5005, and if the exposure control mode is not (M), the program goes tostep #5009. At step #5005, the flash stopping mode is detected. If theflag AMF is set, it is decided that the flash stopping mode is theautomatic flash stopping mode, so that the program goes to step #5006 atwhich the flag AMF is reset to cancel the automatic flash stopping mode.Then, "10" is stored in the indication data AMD at step #5007 so thatthe display circuit FDP indicates that the automatic flash stopping modeis cancelled. Thereafter, at step #5008, "H" is outputted from theterminal P₃₄ so that the flash control circuit FCC ignores the flashstopping signal FSTP transferred from the camera through the terminalJ₆. Thereafter, the program goes to DISP routine (FIG. 32) so that themicrocomputer MCF controls the indicator CHD and outputs the indicationdata, and waits until the next interruption occurs.

If the flag AMF is reset at step #5005, it is decided that the flashstopping mode is not the automatic mode, so that the program goes tostep #5009. At step #5009, the flag AMF is set so that the flashstopping mode is set to the automatic mode, then "01" is stored in theindication data AMD at step #5010 so that the display circuit FDPindicates that the mode is set to the automatic flash stopping mode.Thereafter, "L" is outputted from the terminal P₃₄ so that it ispermitted for the flash control circuit FCC to operate in response tothe flash stopping signal ESTP at step #5011, then the program goes tothe DISP routine (FIGS. 32a and 32b) in which the indicator CHD iscontrolled and the indication data is outputted. Then, the microcomputerMCF waits until the next interruption occurs.

As described above, in the flash emitting device of the camera system ofthe embodiment, when the flag STF is reset, i.e., when the flashemitting device is operating independently of the camera system, theflash stopping mode can be switched regardless of the exposure controlmode. On the other hand, in case that the flag STF is set, i.e., in casethat the flash emitting device becomes operatively connected to thecamera system, the flash stopping mode can be switched only when theexposure control mode is (M), and the flash stopping mode is forciblyswitched to the automatic flash stopping mode when the exposure controlmode is (P), (A), or (S) (automatic exposure mode). Therefore, aphotograph is not carried out in combination of the manual flashstopping mode (flash light is fully emitted) in which the flash stoppingsignal FSTP is ignored and the automatic exposure control mode.

Change-over of illumination range

When the illumination range change-over switch VCS causes theinterruption INTA, the progrom goes to step #5021 at which "1" is addedto the illumination range register FZR. If the content of the registerFZR becomes "101" at step #5022, "000" is stored in the register FZR atstep #5023, that is, the illumination range is set to "automatic". If anillumination range is "automatic", the state of the flag STF is examinedat step #5024.

If the flag STF is set, that is, if the flash emitting device isoperating as part of the camera system, either of data of "001" (28 mm),"010" (35 mm), "011" (50 mm), and "100" (70 mm) is set in theillumination range detecting register (provided in the microcomputerMCF) according to the focal length Fv so that the field angle of thephotographing lens (focal length Fv (apex value)) mounted on the cameracan be covered by the flash light. Then, at step #5025, the emissionpanel is moved to the position corresponding to the data thus set.

If the flag STF is reset at step #5024, that is, if the flash emittingdevice operates independently of the camera system, the data of "001"(28 mm) is set to the illumination range detecting register. Then, atstep #5026, the emission panel is moved to the position nearest theflash emitting device (the position in which the flash light can coverthe field angle of the photographing lens having the focal length of 28mm).

If the content of the register FZR is not "101" at step #5022, namely,not automatic mode, the content of the register FZR is transferred tothe illumination range detecting register. Then, at step #5027, theemission panel is moved to the position in which the flash light coversthe field angle of the photographing lens having the focal length shownby the value of the register FZR.

A more detailed description is made with reference to FIG. 3 with regardto the movement of the emission panel at steps #5025, #5026, and #5027.When the emission panel is moved forward from the current position, forexample, when the content of the register FZR is "011" and the emissionpanel is moved from the position in which the flash light covers thefield angle of the photographing lens having the focal length of 35 mmto the position in which the flash light covers the field angle of thephotographing lens having the focal length of 50 mm and which is forwardfrom the former position, signals are outputted from the terminals P₂₆and P₂₇ to the motor control circuit MDR so that the motor controlcircuit MDR rotates the motor MOFL. As a result, the position detectingcircuit ZCP outputs a signal corresponding to the position of theemission panel, and the signal is transmitted to the terminals P₂₈ andP₂₉ of the microcomputer MCF. When the position of the emission panelindicated by the signal coincides with the position indicated by theillumination range detecting register, a stop signal is transmitted fromthe terminals P₂₆ and P₂₇ to the motor control circuit MDR. In responseto the stop signal, the motor control circuit MDR stops the motor MOFL.When the emission panel is moved backward, the rotational direction ofthe motor MOFL is reversed and the operation to be performed in thiscase is similar to the case in which the emission panel is movedforward.

The illumination range may be changed not only by changing the positionof the emission panel located on the front portion of the emissionportion, but also by changing the configuration of the concave reflectoror by changing the position of the Xe tube which is the emitting source.In addition, the illumination range may also be varied by altering thetransmission characteristic of the emission panel disposed on the frontof the emission portion by mechanically shifting it or byelectro-optically changing the transmission of the emission panel byforming it with an electro-optic element.

Referring to FIGS. 30a, 30b, when the emission panel is moved at steps#5025, #5026, and #5027, data are stored in the indication data FZD atstep #5028 so that the display circuit FDP makes the indication of thefocal length of the photographing lens having the field angle covered bythe flash light and automatic/manual.

That is, if the content of the register FZR is "000", i.e., theillumination range is automatically adjusted, "1" is stored in the mostsignificant bit of the data FZD and any one of "001" (28 mm), "010" (35mm), "011" (50 mm), and "100" (70 mm) is stored in the low-order threebits of the indication data FZD according to the focal lengthinformation Fv transmitted from the camera body. If the content of theregister FZR is not "000", i.e., the illumination range is manuallyadjusted, "0" is stored in the most significant bit of the data FZD andthe content of the register FZR is transferred to the low-order threebits.

Thereafter, the maximum emission amount Iv varied according to thechange of the illumination range is stored in the data FCR₁ at #5029,then the program goes to the DISP routine (FIGS. 32a and 32b).

Change-over of emission mode

FIG. 31 is a flowchart showing the MES routine. When the interruptionINTA is caused by the operation of the emission mode change-over switchMES, the program goes to this routine through steps #5001 and #5002.First, "1" is added to the emission mode register FMR at step #5031. Theregister FMR stores data corresponding to the flash emission mode andwhen the content of the register FMR is "00", "01", and "10", the flashemission mode is the forced emission mode, the automatic emission mode,and the non-emission mode, respectively.

If at step #5032 the content of the register FMR becomes "11" as aresult of the addition of "1" thereto at step #5031, "00" is stored inthe register FMR, that is, the emission mode is switched to the forcedemission mode at step #5033. Thereafter, the state of the flag STF isdetected at step #5034. If the flag STF is set, that is, if the flashemitting device operates as part of the camera system, the program goesto step #5035. If the flag STF is reset, i.e., if the flash emittingdevice operates independently of the camera system, the program skips tostep #5041. It is detected at step #5035 whether or not the exposurecontrol mode of the camera system is (P). If the exposure control modeis (P), "01" is stored at step #5036 in the register FMR to switch theemission mode to the automatic emission mode. If the exposure controlmode is not (P) at step #5035, the program skips to step #5041.

If the content of the register FMR is not "11" at step #5032, theprogram goes to step #5037 at which it is detected whether or not thecontent of the register FMR is "01", i.e., it is detected whether or notthe emission mode is switched to the automatic emission mode. If thecontent of the register is not "01", i.e., if the content of theregister FMR is "10", namely, the emission mode is switched to thenon-emission mode, the program skips to step #5041.

When it is decided at step #5037 that the emission mode is switched tothe automatic emission mode, the program goes to step #5038 so as todetect the state of the flag STF. If the flag STF is set at step #5038,i.e., if the flash emitting device operates as part of the camerasystem, the program goes to step #5039. If the flag STF is reset, i.e.,if the flash emitting device operates independently of the camerasystem, the program skips to step #5041. It is detected at step #5039whether or not the exposure control mode of the camera system is (P). Ifthe exposure control mode is (P), the program skips to step #5041. Ifthe exposure control mode is not (P), the program goes to step #5040 atwhich "10" is stored in the register FMR. That is, the mode is switchedto the non-emission mode.

The summary of the above-described operation is as follows: When theflash emitting device is operating independently of the camera system,the emission mode is switched in the order of the forced emission mode,automatic emission, non-emission, and forced emission according to theoperation of the emission mode change-over switch MES. When the flashemitting device is interlocked with the camera system, the emission modeis switched in response to the switch MES in the order of automaticemission, non-emission, and automatic emission if the exposure controlmode of the camera system is (P), while if the exposure mode controlmode is not (P), the emission mode is switched in response to the switchMES from forced emission, non-emission, to forced emission. That is,when the flash emitting device is operating as part of the camerasystem, the emission mode is switched between the automatic emissionmode and the non-emission mode if the exposure control mode is (P),while when the exposure control mode is either of (A), (S), and (M), theemission mode is switched between the forced emission mode and thenon-emission mode (refer to Tables. 10 and 11.)

When the emission mode is switched according to step #5031 through#5040, the content of the register FMR is transferred at step #5041 tothe high-order two bits FCR₀₆ and FCR₀₇ of the data FCR₀ so that theemission mode is informed to the microcomputer MCB of the camera body.In addition, the content of the register FMR is transferred to theindication data FMD at step #5042 so that the display circuit FDPindicates the emission mode. Then, the program goes to the DISP routine(FIG. 32).

DISP routine

FIGS. 32a and 32b are flowcharts showing the DISP routine. In thisroutine, first, the state of the flag STF is detected at step #5051. Ifthe flag STF is set, the program goes to step #5052. If the flag STF isreset, the program goes to step #5068. As described later, when theprogram goes to step #5068, the display circuit FDP clears the lightamount adjustable-distance range, the film sensitivity Sv, and thecontrol aperture value Av, and the charge completion indicated by theindicator CHD is cleared.

At step #5052, the seventh bit CFR₃₆ of the data CFR₃ is detected. Asdescribed above, when the display circuit FDP and the indicator CHD areallowed to make indications, the seventh bit CFR₃₆ of the data CFR₃ isreset, and when the display circuit FDP and the indicator CHD areprohibited to make indications, the seventh bit CFR₃₆ of the data CFR₃is set. Accordingly, if the seventh bit CFR₃₆ of the data CFR₃ is set,the program goes to step #5068 so that the indications made by thedisplay circuit FDP and the indicator CHD are cleared. If the seventhbit CFR₃₆ of the data CFR₃ is is reset, the program goes to step #5053.

At step #5053, the state of the main capacitor MC is examined. If themain capacitor MC is charged in the predetermined value (for example,300 V), the program goes to step #5054, and if not, the program goes tostep #5067.

The method for detecting the voltage applied to the main capacitor MC isdescribed with reference to FIG. 3.

First, "H" is outputted from the terminal P₃₁ so that the transistor TR₁is conductive. If the charged voltage of the main capacitor MC is lowerthan the predetermined value, the neon tube NE is not discharged, sothat electric current does not flow between the collector and theemitter of the transistor TR₁. Accordingly, electric current does notflow into the charge detecting terminal P₃₂, so that the level of theterminal P₃₂ is "L". Thereafter, when the charged voltage of the maincapacitor MC reaches the predetermined value, the neon tube NE isdischarged, so that electric current flows between the collector and theemitter of the transistor TR₁. Accordingly, electric current flows intothe charge detecting terminal P₃₂, so that the voltage level of theterminal P₃₂ becomes "H". When it is detected that the terminal P₃₂becomes "H", it is decided that the main capacitor MC is charged in thepredetermined voltage.

Returning to FIGS. 32a and 32b, when the main capacitor MC is charged inthe predetermined value at step #5053 and the program goes to step#5054, the sixth bit FCR₀₅ of the data FCR₀ is set so that themicrocomputer MCF informs the microcomputer MCB provided in the camerabody that the main capacitor MC is charged in the predetermined value.Then, at step #5055, "H" is outputted from the terminal P₂₄ so as toturn on the indicator CHD so that the indicator CHD indicates that themain capacitor MC is charged in the predetermined value.

Thereafter, at step #5056, the state of the flash stopping mode ischecked. If the flag AMF is reset, i.e., if the mode is not theautomatic flash stopping mode, the program goes to step #5057, and thedistance at which a correct exposure can be obtained is calculated, andthe data of the calculated distance is stored in the indication data FDDat step #5058 so that the calculated data is indicated by the displaycircuit FDP. The calculation of the distance Dv at which the correctexposure is obtained is performed according to the maximum emissionamount Iv, the aperture value Av transferred from the camera body, andthe film sensitivity information Sv by the following equation:

    Dv=Iv+Sv-Av.

If the flag AMF is set at step #5056, i.e., if the mode is the automaticflash stopping mode, the program goes to step #5059 at which themicrocomputer MCB calculates a distance range in which flash light canbe emitted correctly. The longest photographing distance Dv at which theflash light can be emitted correctly is calculated according to themaximum emission amount Iv, the aperture value Av transferred from thecamera body, and the film sensitivity information Sv by the followingequation:

    Dv=Iv+Sv-Av.

Thereafter, the shortest photographing distance Dv' at which flash lightcan be emitted correctly is calculated according to the minimum emissionamount Iv' by the following equation:

    Dv'=Iv'+Sv-Av.

When the flash emitting device is mounted on the camera body, theshortest photographing distance Dv" in which no parallax is generatedbetween the photograph field angle and the illumination range and thecalculated shortest photographing distance Dv' are compared with eachother so as to adopt the longer photographing distance as the shortestphotograph distance. Thus, a distance range Dv' (or Dv'')˜ Dv in whichflash light can be emitted correctly is calculated. Thereafter, the dataof the distance range Dv' (or Dv")˜ Dv is stored in the indication dataFDD at step #5060.

After the data is stored in the indication data FDD, the filmsensitivity information Sv is stored in the indication data ISD at step#5061 and the aperture value Av is stored in the indication data FND atstep #5062 so that the display circuit FDP indicates the filmsensitivity Sv and the aperture value Av. Then, the microcomputer MCFoutputs at step #5063 the indication data AMD, FDD, FMD, FND, FZD, andISD to the display circuit FDP. Thereafter, the timer counter (T) isreset, i.e., "0" is stored in the timer counter (T), and the operationof the timer provided in the microcomputer MCF is started at step #5064.Then, at steps #5065 and #5066, the microcomputer MCF is enabled for theinterruption of the timer contained therein, the interruptions INTA andINTB caused by the fall of the interruption terminals INTA and INTB. Themicrocomputer MCF waits until either of the interruptions occurs.

When the program goes to step #5067 with detection that the maincapacitor has not been charged in the predetermined value at step #5053,the sixth bit FCR₀₅ of the data FCR₀ is reset to inform this state ofthe microcomputer MCB, and then, the program goes to step #5068 so as toclear the indications made by the display circuit FDP and the indicatorCHD.

At step #5068, first, "L" is outputted from the terminal P₂₄ and theindicator CHD is turned off. Thereafter, the blank indication data BLDare stored in the indication data FDD, ISD, and FND at steps #5069,#5070, #5071 so as to clear the indications of the flash lightamount-adjustable range, the film sensitivity information Sv, and theaperture value Av. Thereafter, the program goes to steps subsequent tostep #5063, and the microcomputer MCF waits until the next interruptionoccurs.

When the program goes to step #5068, the following indications arecleared: The indication of the charge state of the main capacitor MCmade by the indicator CHD, and the indication of the flash lightamount-adjustable range, the film sensitivity information, and theaperture value Av made by the display circuit FDP.

INTB

FIGS. 33a and 33b are flowcharts showing the operation to be performedby the microcomputer MCF when the interruption INTB occurs. Theinterruption INTB is generated by the microcomputer MCB provided in thecamera body.

Referring To FIG. 1, when the flash data CFR₀ through CFR₃ and FCR₀,FCR₁ are transferred between the microcomputers MCB and MCF through theserial data bus SDB, a low level chip select signal CSFL is outputtedfrom the terminal P₂. The signal CSFL is applied to the interruptionterminal INTB of the microcomputer MCF through a contact j₀ (FIG. 3). Insynchronization with the fall of the interruption terminal INTB due tothe chip select signal CSFL, the microcomputer MCF starts its operationin accordance with the flowchart shown in FIGS. 33a and 33b.

First, it is detected at step #5091 whether or not the data FCR₀ andFCR₁ are transferred from the flash emitting device to the camera. Whenthe flash data FCR₀ and FCR₁ are inputted to the microcomputer MCB, themicrocomputer MCB outputs a high level read signal to the read/writedetermining terminal P₂₃ of the microcomputer MCF through a contact J₃.Conversely, when the microcomputer MCB outputs the flash data CFR₀through CFR₃, the microcomputer MCB outputs a low level write signal tothe terminal P₂₃ of the microcomputer MCF (refer to FIG. 3). Then, themicrocomputer MCF checks the state of the terminal P₂₃. If "H" isinputted to the terminal P₂₃, the program goes to step #5092 at whichthe data FCR₀ and FCR₁ are outputted to the camera body. If "L" isinputted to the terminal P₂₃, the program goes to step #5101 at whichthe data CFR₀ through CFR₃ are inputted to the microcomputer MCF.

The input and output of data is described with reference to FIG. 3. Whenthe data CFR₀ through CFR₃, FCR₀, FCR₁ are transferred between the flashemitting device and the camera body, as described above, the low levelchip select signal is inputted from the contact j₀ to the terminal INTB.When the data CFR₀ through CFR₃ are transferred from the camera body tothe flash emitting device, as described above, "L" is inputted from thecontact j₃ to the terminal P₂₃ of the microcomputer MCF. At this time,in synchronization with a reference clock inputted from the contact j₄to the reference clock input terminal SCK, the microcomputer MCF inputsthe data CFR₀ through CFR₃ one bit by one bit through the serial datainput terminal SIN connected to the contact j₁. As described above, whenthe data FCR₀ and FCR₁ are transferred from the flash emitting device tothe camera body, "H" is inputted from the contact j₃ to the terminal P₂₃of the microcomputer MCF. At this time, in synchronization with thereference clock inputted to the terminal SCK, the microcomputer MCFoutputs the data FCR₀ and FCR₁ one bit by one bit from the serial dataoutput terminal SOUT connected to the contact j₂.

Returning to FIG. 33a, after the data FCR₀ and FCR₁ are outputted, thetimer counter (T) is reset to start its operation at step #5093 and themicrocomputer MCF is enabled for a timer interruption by the timer andinterruptions INTA and INTB which occur at the interruption terminalsINTA and INTB at steps #5094 and #5095. Therefore, the microcomputer MCFwaits until either of the interruptions occurs.

After, the data CFR₀ through CFR₃ are inputted to the microcomputer MCFat step #510, it is examined at step #5102 whether or not the exposurecontrol mode is (M). If the contents of the high-order two bits CFR₀₇and CFR₀₆ of the data CFR₀ are "11", it is decided that the exposurecontrol mode is (M), so that the program skips to step #5105. If not"11", the program goes to step #5103. At step #5103, the flag AMF is setto put the mode in the automatic flash stopping mode. Then, "01" isstored in the indication data AMD at step #5104 so that the displaycircuit FDP makes an indication of the automatic flash stopping mode.Then, the program goes to step #5105.

As described above, according to the camera system of the embodiment,when the exposure control mode of the camera system is not (M), theflash stopping mode is forcibly set to the automatic flash stoppingmode.

At step #5105, it is detected whether or not the exposure control modeof the camera system is (P). If the contents of the high order two bitsCFR₀₇ and CFR₀₆ of the data CFR₀ are "00", it is decided that theexposure control mode is (P), then the program goes to step #5106. Ifnot "00", the program goes to step #5107.

At steps #5106 and #5107, the emission mode is examined. It is detectedat step #5106 whether or not the emission mode is the forced emissionmode. If the content of the emission mode register FMR is "00", it isdecided that the emission mode is the forced emission mode, so that theprogram goes to step #5108 at which "10" is stored in the register FMRto switch the emission mode to the nonemission mode. It is detected atstep #5107 whether or not the emission mode is the automatic emissionmode. If the content of the emission mode register FMR is "01", it isdecided that the emission mode is the automatic emission mode. Then, theprogram goes to step #5108 at which "10" is stored in the register FMRto switch the emission mode to the non-emission mode.

After the emission mode is switched to the nonemission mode, at step#5109, the content of the register FMR is stored in the high order twobits FCR₀₇ and FCR₀₆ of the data FCR₀ so that the microcomputer MCFinforms the microcomputer MCB of the state of the emission mode. Then,at step #5110, the content of the register FMR is stored in theindication data FMD so that the display circuit FDP makes an indicationof the emission mode.

As described above, according to the camera system in this embodiment,when the exposure control mode is (P) and the emission mode is theforced emission mode, the forced emission mode is switched to thenon-emission mode. When the exposure control mode is not (P) mode andwhen the emission mode is the automatic emission mode, the automaticemission mode is switched to the non-emission mode (refer to Tables 10and 11).

When the indication data FMD has been set at step #5110, it is detectedat step #5111 whether or not the camera system is reset. If the mostsignificant bit CFR₃₇ of the data CFR₃ is set, it is decided that thecamera system is reset so that program goes to steps #5112 through #5117so as to reset the flash emitting device. If not, the program skips tostep #5118. At step #5112, "01" is stored in the emission mode registerFMR to set the emission mode to the automatic emission mode. At step#5113, the content of the register FMR is stored in the high order twobits FCR₀₇ and FCR₀₆ of the data FCR₀ so that the microcomputer MCFinforms the microcomputer MCB of the emission mode. Then, at step #5114,the content of the register FMR is stored in the indication data FMD sothat the display circuit FDP makes the indication of the emission mode.Thereafter, the microcomputer MCF sets the flag AMF so as to put theflash stopping mode in the automatic flash stopping mode at step #5115.At step #5116, "01" is stored in the indication data AMD so that thedisplay circuit FDP makes the indication of the automatic flash stoppingmode. Then, at step #5117, "000" is stored in the illumination rangeregister FZR to set to the automatic mode.

As described above, when the camera system is reset, the flash emittingdevice is set to the automatic emission mode and the automatic flashstopping mode, and the illumination range is set to the automatic mode.

When the program goes to step #5118 after the above-described operationis completed, the emission panel is moved forward or backward to put theillumination range in the set illumination range. First, it is detectedat step #5118 whether or not the illumination range is automatic. If thecontent of the illumination range register FZR is "000", it is decidedthat the illumination range is automatic, then the program goes to step#5119. As previously described, a signal is outputted to the motorcontrol circuit MDR so that the emission panel is moved to the positionin which the flash light covers the field angle of the photographinglens which is mounted on the camera body and whose focal length is Fv.

If it is decided at step #5118 that the content of the register FZR isnot "000", the program goes to step #5120 at which signals are outputtedfrom the terminals P₂₆ and P₂₇ so that the motor control circuit MDRdrives the motor MOFL, whereby the emission panel is moved. Then, theposition of the emission panel is detected by the signals inputted fromthe position detecting circuit ZCP to the terminals P₂₆ and P₂₇, andwhen the emission panel is moved to the position in which the flashlight covers the field angle of the photographing lens having the focallength indicated by the content of the register FZR, signals areoutputted from the terminals P₂₆ and P₂₇ so that the motor controlcircuit MDR stops the motor MOFL.

When the positioning of the emission panel is completed, similarly tothe execution at step #5028 (FIG. 30b), the indication data FZD is setat step #5121 so that the display circuit FDP provides the indicationsof the focal length of the photographing lens whose field angle iscovered by the flash light and automatic/manual. Then, the maximumemission amount Iv of the flash emitting device is stored in the dataFCR₁ at step #5122, then the program goes to step #5123.

At step #5123, the emission mode of the camera system is detected. Ifthe sixth bit CFR₃₅ of the data CFR₃ is set, it is decided that the modeis the non-emission mode. Then, the program goes to step #5126, and ifnot set, it is decided that the mode is the emission mode, and then, theprogram goes to step #5124.

At step #5124, the charge state of the main capacitor MC is examined. Ifelectric current flows through the terminal P₂₃ to cause the terminalP₂₃ "H", it is decided that the main capacitor MC is charged more thanor equal to a predetermined value, so that the program goes to step#5125. If not "H", the program goes to step #5126. At step #5125, "L" isoutputted from the terminal P₃₅ to allow the flash control circuit FCCto output the emission start signal STA. At step #5126, "H" is outputtedfrom the terminal P₃₅, to prohibiting the flash control circuit FCC fromoutputting the emission start signal STA.

It is possible to determine whether or not the flash light is emittedonly according to the state of the CFR₃₅ by omitting step #5124, whichis described later.

Thereafter, the flag STF is set at step #5127 to indicate that the flashemitting device is operating as part of the camera system. Then, at step#5128, "H" is outputted from the terminal P₃₀ to actuate the DC-to-DCconverter DD. Then, the program goes to DISP routine (FIGS. 32a and32b).

FIG. 34 is a flowchart showing a timer interruption routine.

As described above, the microcomputer MCF is continually enabled for atimer interruption every certain interval (for example, 250 msec.) bythe timer provided in the microcomputer MCF during the operation of themicrocomputer MCF.

First, "1" is added to the timer counter (T) at step #5131. Then, thecontent of the timer counter (T) and the predetermined value (K) arecompared with each other at step #5132. If T<K, the program goes to step#5133. If T≧K, the program goes to step #5144.

At step #5133, it is detected whether or not the DC-to-DC converter DDis in operation. If "H" is outputted from the terminal P₃₀, it isdecided that the DC-to-DC converter DD is in operation, so that theprogram goes to step #5134. If "H" is not outputted, the program skipsto step #5136.

At step #5134, the charged voltage of the main capacitor MC is examined.If electric current flows into the terminal P₃₂ so that the terminal P₃₂is "H", it is decided that the main capacitor MC is charged more thanthe predetermined value, and at step #5135, "L" is outputted from theterminal P₃₀ to stop the operation of the DC-to-DC converter DD. At step#5134, if electric current does not flow into the terminal P₃₂ so thatthe terminal P₃₂ is "L", it is decided that the main capacitor is notcharged in the predetermined value, then the program skips to step#5136.

At step #5136, it is detected whether or not the flash stopping signalFSTP is outputted from the camera body through the contact j₆. If "H" isinputted to the terminal P₃₃, it is decided that the flash stoppingsignal FSTP is outputted from the camera, so that the program goes tostep #5137 at which the fifth bit FCR₀₄ of the data FCR₀ is set. At thesame time, at step #5138, "H" is outputted from the terminal P₂₅ to turnon the indicator FCD, then the program goes to step #5141. If "L" isinputted to the terminal P₃₃, it is decided that the flash stoppingsignal FSTP is not outputted from the camera body, and the fifth bitFCR₀₄ of the data FCR₀ is reset at step #5139. At the same time, "L" isoutputted from the terminal P₂₅ to turn off the indicator FCD at step#5140, then the program goes to step #5141.

At step #5141, the timer counter (T) is reset to start its operation.Then, the microcomputer MCF is enabled for the timer interruption atstep #5142 and for the interruptions INTA and INTB in response to thefall of the interruption terminals INTA and INTB at step #5143, thenwaits until either of the interruptions occur.

At step #5132, if T≧K, the flash emitting device terminates itsoperation as part of the camera system. The flag STF is reset at step#5144 to memorize this. Thereafter, "L" is outputted from the terminalsP₂₄ and P₂₅ to turn off the indicators CHD and FCD at steps #5145 and#5146, and at step #5147, the blank indication data BLD is stored in theindication data AMD, FZD, FMD, FND, ISD, and FDD so that the displaycircuit FDP clears all the indications, and then, the data istransferred to the display circuit FDP at step #5148.

Thereafter, it is detected at step #5149 whether or not the DC-to-DCconverter DD is in operation. If "L" is outputted from the terminal P₃₀,it is decided that the DC-to-DC converter DD is not in operation, sothat the program goes to step #5143. If not, the program goes to step#5150. At step #5150, the voltage of the main capacitor MC is examined.If the voltage thereof reaches the predetermined value, "L" is outputtedfrom the terminal P₃₀ to stop the operation of the DC-to-DC converter DDat step #5151, then the program goes to step #5143. If the voltage ofthe main capacitor MC does not reach the predetermined value, theprogram goes to step #5141 at which the timer counter (T) is reset tostart its operation and at step #5142, the microcomputer MCF allows thetimer interruption. Then, at step #5143, the microcomputer MCF allowsthe interruptions INTA and INTB in response to the fall of theinterruption terminals INTA and INTB, thus waiting until either of theinterruptions occurs.

As described, if the interruption INTA and INTB do not occur for apredetermined period after the interruptions INTA and INTB occur inresponse to the fall of the interruption terminals INTA and INTB, allthe indications of the flash emitting device are cleared and only themain capacitor MC is charged. When the main capacitor MC is charged tothe predetermined voltage, the main capacitor MC is not charged anylonger. Then, the microcomputer MCF waits until either of theinterruptions INTA and INTB in response to the fall of the interruptionterminals INTA and INTB occurs.

SUMMARY

The above is a preferred embodiment of the camera system which embodiesthe present invention. The relationship between the emission mode andthe exposure control mode in the embodiment is summarized of follows:

Table 10 shows the relationship between the emission mode and theexposure control mode of the embodiment.

As described above, when the exposure control mode is (P), the flashemission mode can be switched only between the non-emission mode and theautomatic emission mode. On the other hand, if the exposure control modeis either of the modes (S), (A), and (M), the flash emission mode can beswitched only between the forced emission mode and the non-emissionmode. But when the flash emitting device operates independently of thecamera system, for example, when the flash emitting device is mounted onother cameras, the emission mode can be switched from the forcedemission, the automatic emission, the non-emission to the forcedemission.

                  TABLE 10                                                        ______________________________________                                               exposure control                                                                         flash emission                                                     mode       mode                                                        ______________________________________                                        invention- applicable camera                                                           P mode                                                                                      ##STR5##                                                        S, A, M modes                                                                               ##STR6##                                               invention- inapplicable camera                                                                       ##STR7##                                               ______________________________________                                    

Table 11 shows how the emission mode is switched when the exposurecontrol mode is switched.

When the flash emitting device is mounted on the camera according to thecamera system of the present invention, the flash emission mode isautomatically switched over according to a selected exposure controlmode.

For example, when the exposure control mode is switched from (P) mode toanother mode, the emission mode is switched from automatic emission tothe non-emission or from the non-emission to the non-emission.Conversely, when the exposure control mode is switched from either ofthe modes (S), (A), and (M) to (P), the emission mode is switched fromthe forced emission to the non-emission or from the non-emission to thenon-emission. When the system reset is effected, the mode is alwaysswitched to the automatic emission mode irrespective of a previouslyselected emission mode.

                  TABLE 11                                                        ______________________________________                                        exposure control                                                              mode          flash emission mode                                             ______________________________________                                        P → S, A, M                                                                          automatic emission →                                                                  non-emission                                                   non-emission →                                                                        non-emission                                     S, A, M → P                                                                          forced emission →                                                                     non-emission                                                   non-emission →                                                                        non-emission                                     system reset  forced emission                                                               non-emission →                                                                        automatic                                                      automatic      emission                                                       emission                                                        ______________________________________                                    

Modification First modification

In this embodiment, the relationship between the exposure control modeand the emission mode is not limited to the above-described embodiment,but the embodiment can be modified as shown in Tables 12 and 13.

                  TABLE 12                                                        ______________________________________                                               exposure control                                                                         flash emission                                                     mode       mode                                                        ______________________________________                                        invention- applicable camera                                                           P, S, mode                                                                                  ##STR8##                                                        A, M modes                                                                                  ##STR9##                                               invention- inapplicable camera                                                                       ##STR10##                                              ______________________________________                                    

                  TABLE 13                                                        ______________________________________                                        exposure control                                                              mode          flash emission mode                                             ______________________________________                                        P, S → A, M                                                                          automatic emission →                                                                  forced emission                                                non-emission →                                                                        non-emission                                     A, M → P, S                                                                          forced emission →                                                                     automatic                                                                     emission                                                       non-emission →                                                                        non-emission                                     system reset  forced emission                                                               non-emission →                                                                        automatic                                                      automatic      emission                                                       emission                                                        ______________________________________                                    

In order to modify the embodiment as such, the microcomputers MCB andMCF are controlled as follows (refer to FIGS. 38b, 41, 43, and 45).

Microcomputer MCB

Referring to FIGS. 38a and 41, the program is so changed that it isdetected at step #253 whether the exposure control mode is (P) or (S)and steps #347 and #356 are deleted from the flowchart shown in FIGS.13b and 20. Further, referring to FIG. 42b a step for detecting whetherthe mode is (P) or not is provided subsequent to step #429 (FIG. 23) sothat the program goes to step #430 if the mode is (P), and an (S) modecalculation (Av=Bvc+Sv-Tv) is performed if the mode is not (P), andthen, the program goes to step #431.

Microcomputer MCF

Referring to FIGS. 43 and 45 the program is so changed that it isdetected at steps #5035 and #5039 (FIG. 31) whether the exposure controlmode is (P) or (S) and it is detected at step #5105 (FIG. 33a) whetherthe mode is (P) or (S). Further, the program is so changed that step#5108 is deleted from the flowchart shown in FIG. 33a in which if FMR=00at step #5106, "01" is stored in the register FMR and the program goesto step #5109, and if FMR=01 at step #5107, "00" is stored in theregister FMR, and the program goes to step #5109.

According to this modification, when the exposure control mode is (P) or(S), the emission mode is the automatic emission mode (or thenon-emission mode). When a photograph is taken using a flash light, thesame operation is performed in (P) and (S) modes. When a photograph istaken under natural light without using a flash, the camera systemperforms an operation according to (P) mode or (S) mode. When theexposure mode is (A) or (M), the camera system performs the sameoperation as that performed in the embodiment as previously described.

In this modified embodiment, a slow synchronized photographing isperformed by turning on the AE lock switch ALS when the exposure controlmode is (A) or (M), while a spot measuring photographing is carried outby turning on the AE lock switch ALS when the exposure control mode is(P) mode or (S) mode.

Second modification

In the above-described embodiment, if the main capacitor MC is notcharged to a predetermined voltage, available light photography iscarried out. However, even if main capacitor MC is not charged to thepredetermined voltage, a flash photographing may be carried out. This isbecause, as described above, while the camera system operates, theDC-to-DC converter DD always operates so that the main capacitor MC isbeing charged, i.e., in most cases, the voltage of the main capacitor MCis enough to carry out the flash photographing.

In order to carry out the above-described modification, the controlprocedures of the microcomputers MCB and MCF are altered (refer to FIGS.39, 40, 41, 42a, 42b, and 44.)

Microcomputer MCB

Referring FIGS. 39 and 41, steps #301 through #304 (FIG. 17) and steps#341 through #344 (FIG. 20) are deleted from the flowchart showntherein. Referring to FIG. 40 the flowchart is provided with a step,between steps #325 and #327 (FIG. 18), at which if the main capacitor MCis charged in the predetermined voltage, "01" is stored in theindication data FLD₁, and if not, "00" is stored in the data FLD₁.Further, referring to FIGS. 42a, 42b, and 42c, the flowchart shown inFIG. 23 is so altered that the program goes from step #427 to step #436.Further, the seventh bit CFR₃₆ (FDIS) of the data CFR₃ is reset when aflash photographing is performed and set when available photographing iscarried out.

Microcomputer MCF

Referring to FIG. 44, a step is provided in FIGS. 32a and 32b so that ifthe main capacitor MC is not charged to the predetermined voltage atstep #5053, the program goes to step #5056 through steps #5067 and#5068. In the flowchart shown in 32, if CFR₃₆ =1 at step #5052, theindication made by the indicator CHD that the main capacitor MC ischarged is cleared, then the program goes to step #5069.

According to this modification, it is unnecessary to wait until the maincapacitor MC is charged to the predetermined voltage. Regardless ofwhether or not the main capacitor MC is charged in the predeterminedvoltage, the light amount-adjusting distance range, the filmsensitivity, and the aperture value are indicated in the flash emittingdevice. Further, irrespective of whether or not the main capacitor MC ischarged to the predetermined voltage, the above-described indicationsare not made when available photography is carried out, and if the maincapacitor MC is charged to the predetermined voltage, the indicator CHDdoes not make the indication that the main capacitor has been charged inthe predetermined voltage.

Third modification

In the above-described embodiment or the modifications, when theexposure control mode is (P) ((P) and (S) in the second modification),the slow synchronized photographing is not carried out, but when themanual AE lock is performed by turning on the AE lock switch ALS, a slowsynchronized photographing may be accomplished if the flash emittingdevice is in the emission mode irrespective of the exposure controlmodes. This modification can be effected by altering the controlprocedure of the microcomputer MCB as follows (refer to FIGS. 38a and38b.)

Microcomputer MCB

Referring to FIG. 38a, the program is so altered that whether or not themode is the non-emission mode is detected at step #228 (FIG. 13a). If itis detected that the mode is the non-emission mode, the program goes tostep #259, and if the mode is not the non-emission mode, i.e., if themode is the forced emission mode or the automatic emission mode, theprogram goes to step #230. According to this modification, referring toFIG. 38b, if it is decided at step #251 FIG. 13b that the manual AE lockis made, the program goes to step #252 at which the slow synchronizedphotographing is carried out.

Fourth modification

In the above-described embodiment, the selection of the emission mode iseffected by the flash emitting device, but the flashing operation itselfin accordance with an emission mode is controlled by the microcomputerMCB provided in the camera body. But it is possible that themicrocomputer MCF provided in the flash emitting device detects theemission mode and controls the flashing operation in accordance with theemission mode. Specific examples of altering the control procedure ofthe microcomputers MCB and MCF are described hereinbelow (refer to FIGS.40 and 45b).

Microcomputer MCB

Referring to FIG. 40, step #329 of the α operation routine (FIG. 18) isomitted.

Microcomputer MCF

A step at which it is detected whether or not the mode is thenon-emission mode is provided prior to step #5123 in the flowchart shownin FIG. 33b in which the program goes to step #5126 if the emission modeis the non-emission mode and if the emission mode is not thenon-emission mode, it is detected whether the emission mode is theforced emission mode. If it is determined that the emission mode is theforced emission mode, the program goes to step #5124. If the emissionmode is neither the non-emission mode nor the force emission mode, i.e.,if the emission mode is the automatic emission mode, the program goes tostep #5123.

Fifth modification

In the above-described embodiment, when the luminance Bvs of the mainobject is calculated, necessary measured data is selected from themeasured data Bv0 through Bv5 according to the photographingmagnification β, but measured data may be selected according to the mainzone and the adjacent zone.

Specifically, steps #230 through #243 in FIG. 13b are altered as follows(refer to FIGS. 38c and 38d).

First, which of the zones is the main zone is detected. If the zero zoneis the main zone, it is detected whether or not the first and secondzones are adjacent zones. If the first (second) zone is the main zone,it is detected whether or not the zero zone is the adjacent zone. If thefirst (second) zone is the main zone and the zero zone is the adjacentzone, it is detected whether or not the second (first) zone is theadjacent zone.

If the zero zone is the main zone and both the first and second zonesare the adjacent zones, the luminance Bvs of the main object iscalculated depending on the five measured data Bv0 through Bv4. If thefocal length of the photographing lens is longer than the predeterminedfocal length f₀ (for example, 50 mm), the luminance Bvs of the mainobject is calculated by the weighted mean by making the weights of themeasured data Bv0 through Bv2 large. If the focal length of thephotographing lens is shorter than the predetermined focal length f₀,the luminance Bvs of the main object is calculated by the weight mean inwhich the weight of the measured data Bv0 is large.

If the zero zone is the main zone and only the first (second) zone isthe adjacent zone, the luminance Bvs of the main object is calculateddepending on two measured data Bv0 and Bv1 (Bv2). At this time, theluminance Bvs of the main object is calculated by the weight mean inwhich the weight of the measured data Bv0 is large.

If the zero zone is the main zone and there are no adjacent zones, themeasured data Bv0 is the luminance Bvs of the main object.

If the first (second) zone is the main zone and both the zero and thesecond (first) zones are the adjacent zones, the luminance Bvs of themain object is calculated depending on three measured data Bv0, Bv1, andBv2. At this time, the luminance Bvs of the main object is calculated bythe weighted mean in which the weight of the measured data Bv1 (Bv2) islarge.

If the first (second) zone is the main zone and only the zero zone isthe adjacent zone (if the second (first zone is not the adjacent zone),the luminance Bvs of the main object is calculated depending on the twomeasured data Bv0 and Bv1 (Bv2) by the weight mean in which the weightof the measured data Bv1 (Bv2) is large.

If the first (second) zone is the main zone and there is no adjacentzone, the measured data Bv1 Bv2 is the luminance Bvs of the main object.

This modification allows the luminance Bvs. of the main object to becalculated without finding the photographing magnification β.

Sixth modification

In the above-described embodiment, whether or not the flash emittingdevice is mounted on the camera is detected by the emission mode and soon, but as described below, a flag FONF which indicates whether or notthe flash emitting device is mounted is provided so that it is detectedby the flag FONF whether or not the flash emitting device is mounted(refer to FIGS. 36, 37a, 37b, 38a and 38b).

Specifically, referring to FIG. 36, in the AE routine (FIG. 5), afterthe flash data transferred from the flash emitting device is inputted tothe microcomputer MCB at step #22, the state of the fourth bit FCR₀₃ ofthe data FCR₀ is detected. If the bit FCR₀₃ is set, the flag FONF isset, and if not, the flag FONF is reset. After the indication data isoutputted at step #26, if the flag FONF is reset, the program skips tostep #28, and if the flag FONF is set, the program goes to step #27 sothat the flash data is outputted.

Similarly, referring to FIGS. 37a and 37b in STOP routine (FIG. 8),after the flash data is inputted at step #91, the fourth bit FCR₀₃ ofthe data FCR₀ is examined. If the fourth bit FCR₀₃ is set, the flag FONFis set. If not, the flag FONF is reset. Then, after the indication datais outputted at step #106, the state of the flag FONF is examined. Ifthe flag FONF is reset, the program skips to step #107. If the flag FONFis set, the program goes to step #106 so as to output the flash data.

The subroutine "exposure calculation" (FIGS. 13a and 13b) is modified asfollows: Referring to FIG. 38a, if the flag BLAF is set at step #227,the state of the flag FONF is examined. Referring to FIG. 38a, if theflag FONF is reset, the program goes to step #259 (subroutine "spotlight measuring"). If the flag FONF is set, the program goes to step#228 so as to examine the emission mode. Similarly, referring to FIG.38b, if the flag BLAF is reset at step #251, the state of the flag FONFis examined. If the flag FONF is reset, the program goes to step #256(subroutine "available light"), and if the flag FONF is set, the programgoes to step #253.

In the subroutine "system reset" (FIG. 25), "mode change" (FIG. 26), and"data change" (FIG. 27), the state of the flag FONF is not examined evenimmediately prior to the output of the flash data. This is for thereason described below. When the interruption INT₀ is generated by theoperation either of the switches SRS, MOS, US, and DS in the conditionwhere the camera system is not in operation, the flag FONF is reset (seeSTOP routine (step #108 in FIG. 8) regardless of whether or not theflash emitting device is mounted on the camera body. Accordingly, if thestate of the flag FONF is detected, and the flash data is outputted,only when the flag FONF is set, the subroutine "system reset", etc.,similarly to the AE routine (FIG. 5) steps #26 and #27, trouble as isdescribed below may happen. That is to say, if the interruption INT₀ isgenerated when the camera system is not in operation so that the programgoes to one of the subroutines "system reset", "mode modification", and"data alteration", the flash emitting device is not reset and the mode(e.g. flash emission mode) is not changed even if the flash emittingdevice is mounted on the camera body.

Seventh modification

Next, the modifications of the light measuring pattern are described bymaking reference to FIGS. 46a, 46b, 46c and 46d.

FIG. 46(a) shows a first modification of the light measuring pattern. Inthis light measuring pattern, the light measuring regions (hereinafterreferred to as region(s)) are determined in consideration of thepositions of the CCD line sensors ISL₀ through ISL₂. That is, arectangular region 1a is the region (zero zone) whose center area isused for the CCD line sensor ISL₀. A rectangular region 2a is the region(first zone) whose center area is used for the CCD line sensor ISL₁. Themeasured area of the region 2a is almost equal to that of the region 1a.A rectangular region 3a is the region (second zone) whose center area isused for the CCD line sensor ISL₂. The area of the region 3a is almostequal to that of the region 1a. Regions 4a and 5a are so located as toenclose the regions 1a, 2a, and 3a. The region 4a is disposed in theupper portions of the regions 1a, 2a, and 3a. The region 5a is disposedin the lower portions of the regions 1a, 2a, and 3a. This configurationof the light measuring pattern enables an accurate spot light measuringof the main object (namely, main object) located in the main zone.

FIG. 46(b) shows the second modification of the light measuring pattern.This light measuring pattern is formed by adopting the advantage of thelight measuring pattern shown in FIG. 2 and the light measuring patternof the above-described first modification. That is, a region 1b iscircular and located in the center of the region LMR to be measured.Sector regions 2b and 3b are located on the left and right sides of theregion 1b, respectively. The areas of the regions 2b and 3b are almostequal to that of the region 1b. The regions 4b and 5b are so located asto enclose the regions 1b, 2b, and 3b. The region 4b is located on theupper portion of the regions 1b, 2b, and 3b. The region 5b is located onthe lower portion of the regions 1b, 2b, and 3b. The configuration andarea formed by the addition of the regions 1b, 2b, 3b, 4b, and 5b arethe same as those of the addition of the regions 1, 2, 3, 4, and 5 ofthe light measuring pattern shown in FIG. 2. This configuration of thelight measuring pattern reduces the influence of lights which areincident on the upper and lower portions of the first (second) zonecompared with the light measuring pattern shown in FIG. 2 when the mainobject is located in a small extent on the left (right) relative to thecenter of the field angle FLM.

FIG. 46(c) shows the third modification of the light measuring pattern.In this modification, regions 4 and 5 shown in FIG. 2 are located on theleft and right, that is, a region 4c which is C-shaped is located on theleft of a region 2c, and a region 5c which is C-shaped is located on theright side of a region 3c. This configuration of the light measuringpattern enables a fine light measuring based on the dimension of theobject image regardless of whether the main zone is either of the zerothrough the second zone.

FIG. 46(d) shows the fourth modification of the light measuring pattern.In this modification, the upper and lower portions of the regions 4c and5c of the third modification are removed. This configuration of thelight measuring pattern enables a fine light measuring based on thedimension of the object image regardless of whether the main zone iseither of the zero through the second zone similarly to the thirdmodification. In addition, compared with other light measuring patterns,the light measuring area 6d surrounding regions 1d through 5d is large.Therefore, the sensitivity with respect to the background light isincreased.

In the above-described embodiment and modifications, no light measuringregions are provided between the second and third regions, but anothersecond or third light region may be provided therebetween.

A known means, for example, a mercury switch may be provided to detectwhether an object is photographed with the camera widthwise orlengthwise so that the method for performing the calculations of theluminances of the main object and the background are changed accordingto the direction in which the main object is photographed.

For example, when the main object is photographed widthwise using thelight measuring pattern shown in FIG. 2 and those shown in FIGS. 46(a)and 46(b), the luminance of the background is calculated by setting theweights of the regions 4, 4a, and 4b located on the upper portionsmaller than those of the regions 5, 5a, and 5b. Owing to thisarrangement, the influence of the regions located on the upper portionson which lights are incident from a bright sky. When the main object isphotographed lengthwise, the luminance of the background is calculatedby setting the weights of the values of the lights incident on theregions 4, 4a, and 4b equal to the weights of the values of the lightsincident on the regions 5, 5a, and 5b. When the main object isphotographed lengthwise, if the relationship between the photographingmagnifications β and the predetermined photographing magnifications β₀and β₁ is β₀ <β<β₁, the luminance of the main object is calculated bysetting the weights of the values of the lights incident on the regions2, 2a, and 2b which are normally located on the upper portion smallerthan the weights of the values of the lights incident on the regions 3,3a, and 3b which are normally located on the lower portion.

Similarly, when the main object is photographed widthwise using thelight measuring patterns shown in FIGS. 46(c) and 46(d), the luminancesof the main object and the background are calculated by setting theweights of the regions 2c, 4c, 2d, and 4d located on the left side equalto the weights of the values of the lights incident on the regions 3c,5c, 3d, and 5d located on the right side. When the main object isphotographed lengthwise, if the relationship between the photographingmagnification β and the predetermined photographing magnifications β₁and β₂ is β₁ <β<β₂, the luminance of the background is calculated bysetting the weights of the values of the lights incident on the regions4c and 4d which are normally located on the upper portion smaller thanthe weights of the values of the lights incident on the regions 5c and5d which are normally located on the lower portion. If the relationshipbetween the photographing magnification β and the predeterminedphotographing magnifications β₁ and β₀ is α₀ <β<β₁, the luminance of themain object is calculated by setting the weights of the regions 2c and2d to be small and the luminance of the background is calculated byreducing the weights of the regions 4c and 4d. If the relationshipbetween the photographing magnification β and the predeterminedphtotgraphing magnification β₀ is β<β₀, the luminances of the mainobject and the background are calculated by reducing the weigths of thevalues of the light incident on the regions 4c and 4d or the weights ofthe values of the light incident on the regions 2c, 4c, 2d, and 4d.

When the main object is photographed lengthwise, a means may be providedto detect which of the left and right of the camera is upper so that theluminance of the main object is calculated by reducing the weight of thevalue of the light incident on the region located upwards.

Although the present invention has been fully described by way ofexample with reference to the accompanying drawings, it is to be notedhere that various changes and modifications will become apparent tothose skilled in the art. Therefore, unless such changes andmodifications depart from the scope of the present invention, theyshould be construed as included therein.

What is claimed is:
 1. A light measuring device comprising:first meansfor detecting focusing conditions of a photo-taking lens with respect toobjects present in a plurality of focus detection regions located aboutthe center of a photographing image plane; second means for measuringlight incident on a plurality of first light measuring regions each ofwhich corresponds to each of the focus detection regions, respectively;third means for measuring light incident on a second light measuringregion located around all of the first light measuring regions; andfourth means for measuring light incident on a third light measuringregion located around all of the second light measuring regions.
 2. Alight measuring device as claimed in claim 1, wherein the second meanscomprises a plurality of light measuring units each of which measureslight incident on the first light measuring regions, each lightmeasuring unit being similar in size.
 3. A light measuring device asclaimed in claim 1, wherein the third means comprises a plurality oflight measuring units each of which measures light incident on asub-region into which the second light measuring region is divided.
 4. Alight measuring device as claimed in claim 1, wherein the first meansconsists of three focus detection units each of which detects focusingcondition of an object present in one of the focus detection regionsarranged in a longitudinal direction of the phototgraphing image plane.5. A light measuring device as claimed in claim 1, further comprisingfifth means for detecting a focus detection region where a main objectexists, a sixth means for calculating an exposure value based on aweighted average in which one of the first light measuring regions,corresponding to the detected focus detection region, is weighted morethan others.